Power supplies / Compare

Montech Century II 850W vs Seasonic FOCUS GX-850 (2024)

A

Product A: Montech

Century II 850W

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B

Product B: Seasonic

FOCUS GX-850 (2024)

58 of 66 known

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Only differences

AMontech Century II 850W

BSeasonic FOCUS GX-850 (2024)

General

7 of 12 differ

Series

Century II1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026

FOCUS GX2Press releasethefpsreview.com/2024/09/30/seasonic-launches-focus-2024-series-atx-3-1-power-supplies-with-optisink-technology-and-other-design-innovationsRead 15 October 2026The release names the line FOCUS GX (2024) Series.

Model numbersiMaker identifiers for this exact model and its listed variants. Excludes sibling models and other generations.

Century II 850W1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026Specifications tab: Model Name Century II 850W. The maker prints no part number.

SRP-FGX851-A5A32SF, SRP-FGX851-A5A32SF-WH3Retailer pageeshop.enzure.se/seasonic-focus-gx-850w-atx/cat-p/c/p1005013704Read 15 October 2026Article number FOCUS-GX-850-V4 is Seasonic's retail code for the black unit and is stored as an alias.5Certification listclearesult.com/80plus/node/13568Read 15 October 2026Model SRP-FGX851-A5A32SF (FOCUS GX-850 ATX 3) is the black unit's code.6Retailer pageldlc.com/en/product/PB00647659.htmlRead 15 October 2026LDLC lists the white unit as FOCUS-GX-850-V4-WHITE, a retail code that is stored as an alias.9Retailer pagekakaku.com/item/K0001666012Read 15 October 2026The Japanese listing names the white unit SRP-FGX851-A5A32SF-WH. The black unit's code SRP-FGX851-A5A32SF comes from the 80 PLUS list.

GTIN / EAN

47105627472631Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026Specifications tab: EAN 4710562747263.

4711173878438, 47111738785683Retailer pageeshop.enzure.se/seasonic-focus-gx-850w-atx/cat-p/c/p1005013704Read 15 October 2026EAN 4711173878438 for FOCUS-GX-850-V4 (black). The check digit is valid. Multitronic lists the same EAN for a black unit.7Retailer pagemultitronic.fi/en/products/4400624/seasonic-focus-gx-850-v4-atx-3-1-850w---psu--80-plus-goldRead 15 October 2026EAN 4711173878438, product colour black.8Retailer pageawd-it.co.uk/seasonic-focus-gx-850-850w-atx-3-1-80-gold-modular-power-supply-white-focus-gx-850-v4-white.htmlRead 15 October 2026EAN 4711173878568 for the white FOCUS-GX-850-V4-WHITE. The check digit is valid.

AnnouncediThe maker's first announcement of this model. This is separate from first retail availability.

15 April 20252Press releasemontechpc.com/news-century-iiRead 14 October 2026Launch article dated 2025-04-15. The unit is available from that day (see the Funkykit launch report).

30 September 20242Press releasethefpsreview.com/2024/09/30/seasonic-launches-focus-2024-series-atx-3-1-power-supplies-with-optisink-technology-and-other-design-innovationsRead 15 October 2026Release dated September 30, 2024.

Status

Available8Retailer pagemaxmybuild.com/power-supplies/montech-century-ii-850wRead 14 October 2026Listing shows $89.90 at Amazon and Newegg, updated 14 Oct 2026. Scan UK lists only an open-box unit and calls the model end of life. Tom's Hardware, in its review of 7 September 2026, lists it at Amazon, Newegg and Best Buy.

Available6Retailer pageldlc.com/en/product/PB00647659.htmlRead 15 October 2026The page lists the white unit in stock. Enzure shows the black unit as expected in stock on October 20, 2026.

PredecessoriThe model this one directly replaced, in the same line, tier and size, as the maker or a trusted review names it.

Not available

Not available

SuccessoriThe model that directly replaced this one, in the same line, tier and size. A revision such as a Slim or OLED model does not count when a next generation exists.

Not available

Not available

Launch price (US)iThe maker's US launch MSRP for the stated configuration, excluding tax. Current store prices and later discounts do not qualify.

$89.92Press releasemontechpc.com/news-century-iiRead 14 October 2026Article: Starting at just $89.9. Funkykit lists the 850W model at US$ 89.9, the lowest of the three launch models. US price, no sales tax.3Press articlefunkykit.com/news/montech-introduces-century-ii-power-supplyRead 14 October 2026Century II 850 W: US$ 89.9. The 1050 W is US$ 109.9 and the 1200 W is US$ 129.9.

From $149.992Press releasethefpsreview.com/2024/09/30/seasonic-launches-focus-2024-series-atx-3-1-power-supplies-with-optisink-technology-and-other-design-innovationsRead 15 October 20266Retailer pageldlc.com/en/product/PB00647659.htmlRead 15 October 20268Retailer pageawd-it.co.uk/seasonic-focus-gx-850-850w-atx-3-1-80-gold-modular-power-supply-white-focus-gx-850-v4-white.htmlRead 15 October 20269Retailer pagekakaku.com/item/K0001666012Read 15 October 2026

Launch price (EU)iThe maker's euro launch price for the stated configuration, including VAT as published. Current store prices and later discounts do not qualify.

Not available

From €139.92Press releasethefpsreview.com/2024/09/30/seasonic-launches-focus-2024-series-atx-3-1-power-supplies-with-optisink-technology-and-other-design-innovationsRead 15 October 20266Retailer pageldlc.com/en/product/PB00647659.htmlRead 15 October 20268Retailer pageawd-it.co.uk/seasonic-focus-gx-850-850w-atx-3-1-80-gold-modular-power-supply-white-focus-gx-850-v4-white.htmlRead 15 October 20269Retailer pagekakaku.com/item/K0001666012Read 15 October 2026

MarketsiISO country or region codes where this exact model or variant is sold. A source page's language does not establish availability.

Not available

US, EU2Press releasethefpsreview.com/2024/09/30/seasonic-launches-focus-2024-series-atx-3-1-power-supplies-with-optisink-technology-and-other-design-innovationsRead 15 October 2026The release lists a USA price and a Europe price. Other regions are named only as rest of world.

ColoursiThe maker's own colour names

Metallic Silver1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026Overview text: a sleek metallic silver finish. The maker names no other colour for this wattage.

Black, White2Press releasethefpsreview.com/2024/09/30/seasonic-launches-focus-2024-series-atx-3-1-power-supplies-with-optisink-technology-and-other-design-innovationsRead 15 October 2026The model table lists the GX-850 and the GX-850 White.6Retailer pageldlc.com/en/product/PB00647659.htmlRead 15 October 2026The listing is for the white unit.

Form factoriThe physical size standard that decides what fits in the case. An ATX unit is 150 × 86 mm at the back. An SFX unit is 125 × 63.5 mm.

ATX1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026Specifications tab: Form Factor ATX (140).5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026DUT Information: Type ATX12V. The maker lists form factor ATX (140).

ATX3Retailer pageeshop.enzure.se/seasonic-focus-gx-850w-atx/cat-p/c/p1005013704Read 15 October 2026The page copies Seasonic's spec table. Form Factor ATX/EPS, 140 mm (L) x 150 mm (W) x 86 mm (H), which is the ATX back face of 150 x 86 mm.

ATX versioniThe ATX12V design guide revision the maker claims compliance with. A 16-pin GPU cable alone does not establish ATX 3.x. A Cybenetics report that withholds its ATX badge does not change the maker's claim. It goes in the source note.

ATX 3.11Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026Overview: ATX 3.1 and PCIe 5.1 platform support. The 80 PLUS certificate type line reads ATX 3.0, ATX 3.1.

ATX 3.12Press releasethefpsreview.com/2024/09/30/seasonic-launches-focus-2024-series-atx-3-1-power-supplies-with-optisink-technology-and-other-design-innovationsRead 15 October 2026Key features: ATX 3.1 and PCIe 5.1.

PCIe CEM versioniThe PCI Express card power revision the maker claims, as printed next to the ATX version. It sets the GPU power connector rules. It is not a slot speed. A reviewer's statement is not enough.

PCIe 5.11Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026Overview: ATX 3.1 and PCIe 5.1 platform support.

PCIe 5.12Press releasethefpsreview.com/2024/09/30/seasonic-launches-focus-2024-series-atx-3-1-power-supplies-with-optisink-technology-and-other-design-innovationsRead 15 October 2026Key features: ATX 3.1 and PCIe 5.1.

Modular cablesiFull means every cable detaches. Semi means some cables are fixed, usually the 24-pin and CPU cables.

Fully modular1Maker product pagemontechpc.com/century-ii-850wRead 14 October 20265Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026DUT Information: Cable Design Fully Modular.

Fully modular2Press releasethefpsreview.com/2024/09/30/seasonic-launches-focus-2024-series-atx-3-1-power-supplies-with-optisink-technology-and-other-design-innovationsRead 15 October 2026Key features: Fully Modular Cabling Design, with a native 12V-2x6 cable.4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Technical specifications: Modular Design Yes (Fully). The modular panel has eleven sockets including a native 12V-2x6 socket.

Built by (OEM)iThe company that designed and built the unit for the brand, such as CWT or FSP. As named by the maker, a teardown review or a Cybenetics report.

Shenzhen Xinweiye Technology (XWY)5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026DUT Information: OEM/ODM Shenzhen Xinweiye Technology Co., Ltd. Tom's Hardware calls the company XWY.7Reviewtomshardware.com/pc-components/power-supplies/montech-century-ii-gold-850w-atx-3-1-power-supply-reviewRead 14 October 2026Internal Design: the OEM is Shenzhen Xinweiye Technology Co., typically referred to as XWY.

Seasonic4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Technical specifications and Part Analysis: Manufacturer (OEM) Seasonic. Review dated October 13, 2024.

Power

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Rated continuous poweriThe continuous DC output the maker rates the unit for, such as 850. Peak or power excursion figures are not stored here.

850W1Maker product pagemontechpc.com/century-ii-850wRead 14 October 20265Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026Manufacturer-provided information: Rated Power 850 W.

850W3Retailer pageeshop.enzure.se/seasonic-focus-gx-850w-atx/cat-p/c/p1005013704Read 15 October 2026Total continuous power 850 W.

Full power rated up toiThe ambient temperature up to which the maker rates full continuous power, such as 50 °C. A review table that prints 0-50 °C with no maker source is not enough. An operating temperature range that does not say full power is not enough. A maker table with load steps gives the full-load row, such as 40 °C at full load next to 50 °C at 80 percent load. A temperature that a Cybenetics report marks as manufacturer-provided counts as a maker statement.

40°C1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026Specifications tab: Operating Temperature 0-40 C. Tom's Hardware prints the power table as Rated @ 40 C. The Cybenetics report leaves its continuous full load temperature row empty.7Reviewtomshardware.com/pc-components/power-supplies/montech-century-ii-gold-850w-atx-3-1-power-supply-reviewRead 14 October 2026Power specifications table titled Rated @ 40 C. Same figure as the maker's operating temperature.

50°C3Retailer pageeshop.enzure.se/seasonic-focus-gx-850w-atx/cat-p/c/p1005013704Read 15 October 2026Operating Temperature 0 - 50 C. The table does not say full power. The Hardware Busters spec table labels the same 0 - 50 C as continuous full load, so 50 is stored.4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Technical specifications: Operating Temperature (Continuous Full Load) 0 - 50 C. Seasonic's own table prints 0 - 50 C as the operating temperature. The review also lists delivering full power at 46 C as a plus.

12V rail designiHow the maker splits +12V over-current protection. Switchable means the user picks single or multi rail with a switch or in software.

Single rail5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026Power Specifications: one +12V column with 70.8A and 849.6W, and one OCP result for 12V.

Single rail4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Technical specifications: Number of 12V rails 1.

+12V max currentiHighest combined current on +12V from the maker's power table. For a multi-rail unit this is the combined total, not one rail.

70.8A1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026DC Output table: +12V 70.8A, 849.6W.5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026

70A3Retailer pageeshop.enzure.se/seasonic-focus-gx-850w-atx/cat-p/c/p1005013704Read 15 October 2026DC output: +3.3 V 20 A, +5 V 20 A, +12 V 70 A, -12 V 0.3 A, +5 VSB 3 A.4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Power Specifications table: +12V 70 A.7Retailer pagemultitronic.fi/en/products/4400624/seasonic-focus-gx-850-v4-atx-3-1-850w---psu--80-plus-goldRead 15 October 2026Max output current (+12V) 70 A.

+12V max poweriHighest combined power on +12V from the maker's power table.

849.6W1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026DC Output table: +12V 70.8A, 849.6W.5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026

840W4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Power Specifications table: +12V 840 W. The spec list also prints Power 12V combined 850W, which is the unit total, so the table figure of 840 W is stored. Multitronic copies 70 A and 840 W from the maker.7Retailer pagemultitronic.fi/en/products/4400624/seasonic-focus-gx-850-v4-atx-3-1-850w---psu--80-plus-goldRead 15 October 2026Combined power (+12V) 840 W.

+3.3V and +5V combined poweriThe combined limit for the +3.3V and +5V rails from the maker's power table. A table that prints the same figure under both rails, as be quiet! does, shows one shared limit, so the figure is stored once and not added.

100W1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026DC Output table prints +3.3V 20A 100W and +5V 20A 100W. The Cybenetics power table has one merged 100W cell for 3.3V and 5V, so 100W is the combined limit.5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026

100W4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Power Specifications table: 5V + 3.3V 100 W. Multitronic prints 100 W under both rails, so the figure is one shared limit.7Retailer pagemultitronic.fi/en/products/4400624/seasonic-focus-gx-850-v4-atx-3-1-850w---psu--80-plus-goldRead 15 October 2026Combined power (+3.3V) 100 W and (+5V) 100 W, which is one shared limit.

+5V standby currentiHighest current on the +5VSB standby rail. It powers USB charging and wake functions while the PC is off.

3A1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026DC Output table: +5VSB 3A, 15W.5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026

3A3Retailer pageeshop.enzure.se/seasonic-focus-gx-850w-atx/cat-p/c/p1005013704Read 15 October 2026DC output: +5 VSB 3 A.4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Power Specifications table: 5VSB 3 A, 15 W.

AC input voltageiThe rated AC input range, such as 100 to 240 V.

Lowest100Highest240V1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026AC Input 100-240 VAC, 50-60 Hz, 10 A max.5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026Manufacturer-provided information: 100-240 Vrms, 10 A, 50-60 Hz.

Lowest100Highest240V3Retailer pageeshop.enzure.se/seasonic-focus-gx-850w-atx/cat-p/c/p1005013704Read 15 October 2026AC input 100 V - 240 V, 50 Hz - 60 Hz, full range.

Alternative low power mode (ALPM)iThe maker or a Cybenetics report states support for the ATX alternative low power mode used by Modern Standby.

Yes5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026Temperature and Compliance Info: ALPM compatible, checked.

Yes4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Technical specifications: Alternative Low Power Mode support Yes. The PSU Timings page says the PSU supports Alternative Low Power Modes.

Certifications

0 of 5 differ

80 PLUS ratingiThe 80 PLUS level. When the 80 PLUS listing or certificate and the maker claim differ, store the listing level and put the claim and test voltage in the source note. When a model has several 80 PLUS entries, such as a newer test at a higher level, use the newest entry that matches the current maker documents.

80 PLUS Gold6Certification listclearesult.com/80plus/sites/80plus/files/manufacturer-certificate/MONTECH_CENTURY%20II%20850W_850W_SOCE%207850_Report.pdfRead 14 October 202680 PLUS ID 7850, model CENTURY II 850W: Gold at 115V, test date 2025-06-04. The certificate lists no sample serial. The maker's own product page says Platinum, which is the Cybenetics level.

80 PLUS Gold5Certification listclearesult.com/80plus/node/13568Read 15 October 202680 PLUS ID 7436, model SRP-FGX851-A5A32SF (FOCUS GX-850 ATX 3), Gold, 115V Internal, certified 06/06/2024, 850 W, 91.61 percent at 50 percent load. The certificate lists no sample serial, so the match is by model code and wattage.

Cybenetics efficiency at 115ViThe Cybenetics ETA level from the 115V test. The Cybenetics report wins over the maker's claim.

Cybenetics Platinum5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026Report 25PS2813A, certification ID 252813, issued May 13, 2025. The database name is Montech Century II Gold 850 ATX3. The badge is ETA Platinum at 115V.

Cybenetics Platinum4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Technical specifications: Cybenetics Efficiency [115V] Cybenetics Platinum (89-91%). Seasonic's spec table also says Cybenetics Efficiency Level Platinum with no voltage. The average efficiency chart shows 89.03 percent, which meets the Platinum limit of 89 percent that the review names. The Cybenetics database feed has no report for this 2024 unit. Its report 3202 for a Focus GX-850 (ATX3.1) tested in March 2026 rates it Platinum for the sample it received, which has a different fan model and cable set, so it is not used.

Cybenetics efficiency at 230ViThe Cybenetics ETA level from the 230V test. The 230V thresholds are higher, so the level can differ from the 115V level. The Cybenetics report wins over the maker's claim.

Cybenetics Platinum5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026ETA Platinum at 230V.

Cybenetics Platinum4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Technical specifications: [230V] Cybenetics Platinum (91-93%). The 230V chart shows 91.3 percent, above the review's Platinum limit of 91 percent.

Cybenetics noise at 115ViThe Cybenetics LAMBDA level from the 115V test. A++ is the quietest. The Cybenetics report wins over the maker's claim.

A-5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026LAMBDA A- at 115V.

A-4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Technical specifications: Noise Cybenetics A- (25-30 dB[A]). The 115V average noise chart shows 28.44 dBA, inside that range. Seasonic's spec table also says Cybenetics Noise Level A-. The later Cybenetics report 3202 rates its sample A, which is not used.

Cybenetics noise at 230ViThe Cybenetics LAMBDA level from the 230V test. The Cybenetics report wins over the maker's claim.

A-5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026LAMBDA A- at 230V.

A-4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026The same A- range of 25-30 dB[A] applies. The 230V average noise chart shows 28.39 dBA. The review does not print a separate 230V level.

Measured

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Average efficiency at 115V (measured)iAverage efficiency over the whole load range at 115V input, from more than 1450 load combinations in the Cybenetics method. It is not the peak efficiency or the efficiency at 50% load.

89.8%5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026Average over more than 1450 load combinations at 115V. Tested May 10, 2025, ambient 28-32 C. The report lists no sample serial.

89.03%4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Average Efficiency chart, 115V AC input: 89.03 percent. The Cybenetics database has no report for this 2024 unit. Cybenetics report 3202 (March 2026, different fan model and cable set) lists 89.635 percent and is not used.

Average efficiency at 230V (measured)iThe same average efficiency at 230V input.

91.84%5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026Average over more than 1450 load combinations at 230V.

91.3%4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Average Efficiency chart, 230V AC input: 91.3 percent.

Light-load efficiency at 115V (measured)iEfficiency at a 10 W load for units up to 500 W, or at a 2% load for larger units, at 115V input. This is the ATX light-load test.

70.357%5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026Efficiency at 2% load (more than 500 W unit) at 115V.

71.39%4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Efficiency chart at 2 percent load (a unit above 500 W) at 115V: 71.39 percent. The review says the unit passes the 70 percent ATX 3.1 recommendation.

Average power factor at 115V (measured)iAverage power factor over the whole load range at 115V input. 1 is the best possible value.

0.9855Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026Average over more than 1450 load combinations at 115V. At 230V it is 0.945.

0.9794Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Average PF chart, 115V AC input: 0.979.

Average noise at 115V (measured)iAverage noise over the whole load range at 115V input in the Cybenetics method, at about 30 °C ambient. It is not the noise at full load.

26.89dB(A)5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026Average over more than 1450 load combinations at 115V, ambient 28-32 C, Bruel and Kjaer 2270 G4 sound analyzer. The 230V average is 26.26 dBA.

28.44dB(A)4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Average Fan Noise chart, 115V AC input: 28.44 dBA. The review's fan noise maps run at 28-32 C ambient. The review calls the average noise not that low for the category.

Noise at full load at 115V (measured)iNoise at 100% load at 115V input in the Cybenetics typical load tests. That row often runs at about 45 °C intake. The intake temperature and the fan speed go in the source note. Lower is better.

42.1dB(A)5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026Typical load tests at 115V, 100% load row: 42.1 dB(A) at 1698 rpm fan speed, ambient about 30 C.

42dB(A)4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Load regulation table at 115V, 100 percent load row: 42 dB(A) at 1545 rpm with 45.29 C intake and 56.76 C exhaust. The row at 110 percent load shows 51.2 dB(A).

Standby power with no load at 115V (measured)iPower the unit draws from the wall with the PC off and nothing drawn from +5VSB, at 115V input.

0.073W5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026Standby power consumption at 115V with no load on +5VSB: 0.0730 W. At 230V it is 0.1474 W.

0.07W4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Standby Power Consumption chart, 115V AC input: 0.07 W. The chart shows two decimals.

Hold-up time (measured)iHow long the outputs stay in regulation after AC power is lost, at maximum continuous load, as printed in the Cybenetics report. The report names no input voltage. The AC loss to PWR_OK time goes in the source note. Higher is better.

22.4ms5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026Hold-Up Time and PWR_OK Signal: hold-up time 22.4 ms, AC loss to PWR_OK 14.3 ms, at maximum continuous load.

23.2ms4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026PSU Timing chart, hold-up time: 23.2 ms. The input voltage and the load are not stated in the chart.

12V ripple at full load (measured)iPeak-to-peak ripple on the +12V rail at full load and 115V input. Lower is better.

28.25mV5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026Non-accredited. 12V ripple at full load at 115V. At 230V it is 29.21 mV.

24.38mV4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026+12V Ripple (Full Load) chart, 115V AC input: 24.38 mV. The ripple table lists 24.4 mV at 100 percent load.

12V load regulation (measured)iHow far the +12V voltage moves between light and full load at 115V input. Lower is better.

0.39%5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026Non-accredited. 12V load regulation at 115V. At 230V it is 0.27%.

0.92%4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Load Regulation +12V chart, 115V AC input, deviation: 0.92 percent. The review says the 12V rail starts low at its 20 W point (11.907 V) and the figure would be 0.28 percent with the 40 W point as the reference.

Cables and connectors

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CablesiOne row per kind of cable that runs from the PSU to a device. Connector is the plug at the device end. Count is the number of those plugs over all cables in the row. Length runs from the PSU end to the first plug. Adapters that plug into other cables are left out. Use 16-pin PCIe when the maker names a 16-pin GPU cable without saying 12V-2x6 or 12VHPWR. A cable from a 12V-2x6 socket on the PSU to 8-pin plugs is a cable, not an adapter, and counts as PCIe 8-pin. When the maker's documents name one GPU cable both 12VHPWR and 12V-2x6, use 16-pin PCIe and name both in the source note. Cables of one connector kind with different lengths or wire gauges get one row each.

AMontech Century II 850W

Connector	Connectors	Cables	Length to first plug (mm)	Wire gauge	Rated power (W)
ATX 24-pin (20+4)	1	1	590	18AWG	Not available
CPU 8-pin (EPS, 4+4)	2	2	700	18AWG	Not available
PCIe 8-pin (6+2)	4	2	600	18AWG	Not available
12V-2x6	1	1	600	16AWG	600
SATA power	8	2	500	18AWG	Not available
4-pin Molex	4	1	500	18AWG	Not available

Source1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026Cables table: 1 motherboard cable with a 20+4 pin plug, 2 CPU cables with one 4+4 pin plug, 2 PCIe cables with two 6+2 pin plugs, 1 12V-2x6 cable, 2 SATA cables with 4 plugs and 1 Molex cable with 4 plugs. Lengths and gauge come from the Cybenetics report.5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026Cables and Connectors table: ATX 20+4 pin 590 mm 18AWG, 2 x 4+4 pin EPS 700 mm 18AWG, 2 x 6+2 pin PCIe cables 600 mm then 150 mm with 4 plugs in total 18AWG, 12+4 pin PCIe 600 mm (600W) 16-26AWG, 2 SATA cables of 500 mm plus 3 x 150 mm spacing with 8 plugs in total 18AWG, 1 Molex cable 500 mm plus 3 x 150 mm with 4 plugs 18AWG. The 16-26AWG range of the 12V-2x6 cable includes the thin sideband wires, so the stored gauge is the 16AWG power wire.

BSeasonic FOCUS GX-850 (2024)

Connector	Connectors	Cables	Length to first plug (mm)	Wire gauge	Rated power (W)
ATX 24-pin (20+4)	1	1	610	16-18AWG	Not available
CPU 8-pin (EPS, 4+4)	2	2	700	16AWG	Not available
PCIe 8-pin (6+2)	3	3	750	16-18AWG	Not available
12V-2x6	1	1	700	16AWG	600
SATA power	8	2	500	18AWG	Not available
4-pin Molex	3	1	450	18AWG	Not available

Source3Retailer pageeshop.enzure.se/seasonic-focus-gx-850w-atx/cat-p/c/p1005013704Read 15 October 2026Seasonic's cable table: MB (24/20 pins) 610 mm 1 cable, CPU (8/4 pins) 700 mm 2 cables, PCIe (8/6 pins) 750 mm 3 cables, SATA 950 mm with 4 plugs on 2 cables, Molex 690 mm with 3 plugs on 1 cable, 12V-2x6 700 mm 1 cable. The SATA and Molex lengths run to the last plug. Hardware Busters gives the first-plug lengths 500 mm for SATA and 450 mm for Molex, which add up to 950 and 690 mm, so the first-plug lengths are stored. Hardware Busters measured 750 mm for the CPU cables and the maker's 700 mm is stored.4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Modular Cables table: ATX 20+4 pin 610 mm 16-18AWG, 4+4 pin EPS12V 750 mm 2 cables 16AWG, 6+2 pin PCIe 750 mm 3 cables 16-18AWG, 12+4 pin PCIe 700 mm (600W) 16-24AWG, SATA 500+150+150+150 mm 2 cables with 8 plugs 18AWG, 4-pin Molex 450+120+120 mm 1 cable with 3 plugs 18AWG, no in-cable capacitors. The 16-24AWG range of the 12V-2x6 cable includes the thin sideband wires, so the stored gauge is the 16AWG power wire. The review says the 12V-2x6 cable is set for 600 W. Its box photo shows 10 cables.6Retailer pageldlc.com/en/product/PB00647659.htmlRead 15 October 2026Power connectors: 2 x +12V (P8, 2 x P4), 8 x Serial ATA, 1 x ATX 24 pin, 3 x Molex (4 pin), 3 x PCI Express 6+2 pin, 1 x PCI Express 16 pin (12V-2x6).

CPU (EPS) connectorsi8-pin or 4+4-pin CPU power plugs.

2=CalculatedFrom Cables

2=CalculatedFrom Cables

PCIe 8-pin connectorsi8-pin or 6+2-pin GPU power plugs. Counts the plugs in the box. Some cables share one PSU socket, which the source note says.

4=CalculatedFrom Cables

3=CalculatedFrom Cables

16-pin GPU connectorsiNative 16-pin GPU power plugs: 12V-2x6, 12VHPWR and 16-pin cables of unstated revision. Adapters are not counted. Counts the plugs in the box. Some cables share one PSU socket, which the source note says.

1=CalculatedFrom Cables

1=CalculatedFrom Cables

SATA power connectors

8=CalculatedFrom Cables

8=CalculatedFrom Cables

4-pin Molex connectors

4=CalculatedFrom Cables

3=CalculatedFrom Cables

Cable styleiHow the modular cables are made. Mixed means some cables are sleeved and others flat, such as a sleeved 24-pin cable with flat other cables. From the maker page or a review photo page.

Flat1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026Overview: Flat cables and fully modular design.7Reviewtomshardware.com/pc-components/power-supplies/montech-century-ii-gold-850w-atx-3-1-power-supply-reviewRead 14 October 2026The cable bundle is all-black and entirely flat-ribbon in construction.

Sleeved3Retailer pageeshop.enzure.se/seasonic-focus-gx-850w-atx/cat-p/c/p1005013704Read 15 October 2026Cable type: Individual Black Cables with Braided Pattern. Hardware Busters photos show a separate braided-texture sleeve on each wire.4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Cable photos show black cables with a braided-texture sleeve on each wire.10Reviewalktech.co/articles/unboxing-overview-seasonic-focus-gx-atx-3.1-850w-power-supply-unitRead 15 October 2026All cables feature a braided-pattern design.

Fan

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Fan sizeiFrame size of the cooling fan, such as 120, 135 or 140.

135mm1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026Specifications tab: Fan Size 135 mm.5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026DUT Information: 135mm Fluid Dynamic Bearing Fan.

135mm2Press releasethefpsreview.com/2024/09/30/seasonic-launches-focus-2024-series-atx-3-1-power-supplies-with-optisink-technology-and-other-design-innovationsRead 15 October 2026Key features: 135 mm Fluid Dynamic Bearing (FDB) Fan.3Retailer pageeshop.enzure.se/seasonic-focus-gx-850w-atx/cat-p/c/p1005013704Read 15 October 2026Fan Size 135 mm, Fan Control Digital Hybrid Fan Control.4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Part Analysis: Hong Hua HA13525H12F-Z, 135 mm, 12 V, 0.50 A.

Fan bearingiUse the maker's bearing name. FDB and S-FDB are fluid dynamic. HDB is hydrodynamic. Noctua SSO and SSO2 are SSO. Corsair Magnetic Dome is magnetic dome. A brand bearing name that fits no option is Other.

Fluid dynamic (FDB)1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026Specifications tab: Fan Bearing FDB.5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026DUT Information: 135mm Fluid Dynamic Bearing Fan (HA13525M12SF-Z).

Fluid dynamic (FDB)2Press releasethefpsreview.com/2024/09/30/seasonic-launches-focus-2024-series-atx-3-1-power-supplies-with-optisink-technology-and-other-design-innovationsRead 15 October 2026Key features: 135 mm Fluid Dynamic Bearing (FDB) Fan.3Retailer pageeshop.enzure.se/seasonic-focus-gx-850w-atx/cat-p/c/p1005013704Read 15 October 2026Fan Bearing: Fluid Dynamic Bearing, life expectancy 50,000 hours at 40 C.4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Part Analysis: Fluid Dynamic Bearing fan.

Fan modeiSemi-passive means the fan stops at low load, often sold as zero RPM, hybrid or 0 dB mode. Fanless means the unit has no fan.

Semi-passive1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026Overview: 135 mm FDB fan with Smart Zero Fan mode.5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026DUT Information: Semi-Passive Operation checked (selectable).

Semi-passive4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Technical specifications: Semi-Passive Operation yes (selectable). The 10 to 20 percent load rows run at 0 rpm.

Fan mode switchiA button, switch or software setting lets the user turn the semi-passive mode off so the fan always spins. A unit without a semi-passive mode, whose fan the maker says always spins, has no switch, so it is false.

Yes5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026DUT Information: Semi-Passive Operation marked selectable.7Reviewtomshardware.com/pc-components/power-supplies/montech-century-ii-gold-850w-atx-3-1-power-supply-reviewRead 14 October 2026External Appearance: a smaller secondary toggle on the rear lets the user disable the hybrid mode and run the fan continuously.

Yes4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026The front panel has a switch that toggles the fan's semi-passive operation on or off.10Reviewalktech.co/articles/unboxing-overview-seasonic-focus-gx-atx-3.1-850w-power-supply-unitRead 15 October 2026A Hybrid Mode button on the front enables or disables the Digital Hybrid Fan Control, which is the fan-less operation mode.

Protection and parts

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ProtectionsiProtections the maker lists, or a retailer spec table copies from the maker, plus protections the Cybenetics protection tests show working (UVP, NLO, SIP). The Cybenetics manufacturer list has no OVP or UVP row, so do not build the list from it alone. A protection that is not listed may still exist. No-load covers no-load operation and no-load protection. Fan failure is a maker's fan failure protection or fan safeguard, also when the Cybenetics manufacturer block lists it.

Over-current (OCP), Over-voltage (OVP), Under-voltage (UVP), Over-power (OPP), Over-temperature (OTP), Short-circuit (SCP), No-load (NLO), Surge and inrush (SIP)1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026Specifications tab: OPP / OVP / UVP / SCP / OCP / OTP.5Measurementcybenetics.com/evaluations/psus/2813Read 14 October 2026Protection Features (Manufacturer) lists OPP, +12V OCP, OTP, SCP, surge and inrush current protection. Protection tests tick UVP at 90 V and 80 V and NLO. The maker lists OVP, which the report does not test.

Over-current (OCP), Over-voltage (OVP), Under-voltage (UVP), Over-power (OPP), Over-temperature (OTP), Short-circuit (SCP), No-load (NLO), Surge and inrush (SIP)3Retailer pageeshop.enzure.se/seasonic-focus-gx-850w-atx/cat-p/c/p1005013704Read 15 October 2026Protection: OCP, OPP, OTP, OVP, SCP, UVP.4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Protection Features page: OCP, OPP, OTP, SCP, NLO and SIP (surge MOV, inrush NTC and bypass relay) are ticked. Fan failure protection is not present. The Part Analysis lists a Weltrend WT7527RA supervisor IC with OVP, UVP, OCP, SCP and PG. Seasonic's table lists OVP and UVP.

All-Japanese capacitorsiThe maker states that every electrolytic capacitor is from a Japanese maker. A Japanese bulk capacitor alone is not enough. A spec row such as "Japanese capacitors" that names no exception counts.

Yes1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026Overview: 100% Japanese capacitors. The launch article says 100% Japanese electrolytic capacitors.2Press releasemontechpc.com/news-century-iiRead 14 October 2026Article: 100% Japanese electrolytic capacitors.

Yes2Press releasethefpsreview.com/2024/09/30/seasonic-launches-focus-2024-series-atx-3-1-power-supplies-with-optisink-technology-and-other-design-innovationsRead 15 October 2026Key features: Highly Reliable Japanese 105 C Aluminum Electrolytic Capacitors. The wording names no exception. Hardware Busters lists only Japanese brands for the electrolytic capacitors and also 18 FPCAP and 5 Nippon Chemi-Con polymer capacitors.4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Part Analysis lists the electrolytic capacitors as Nichicon, Nippon Chemi-Con and Rubycon, and the polymer capacitors as Nippon Chemi-Con and FPCAP.

MTBF (claimed)iThe maker's mean time between failures, such as 100000. An MTTF figure for the whole unit counts too. An MTTF for the fan alone does not. The test temperature goes in the source note.

Not available

100,000h3Retailer pageeshop.enzure.se/seasonic-focus-gx-850w-atx/cat-p/c/p1005013704Read 15 October 2026MTBF at 25 C, excluding the fan: 100,000 hours.7Retailer pagemultitronic.fi/en/products/4400624/seasonic-focus-gx-850-v4-atx-3-1-850w---psu--80-plus-goldRead 15 October 2026Mean time between failures 100000 h.

Monitoring and lighting

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Software monitoringiThe unit reports power, temperature or fan data to PC software over a USB or internal connection.

Not available

Not available

SoftwareiThe maker's software for monitoring or control.

Not available

Not available

Built-in power displayiA screen on the unit that shows live power draw or other readings.

Not available

Not available

RGB lighting

No8Retailer pagemaxmybuild.com/power-supplies/montech-century-ii-850wRead 14 October 2026Listing specs: no RGB. Tom's Hardware and the maker page describe no lighting.

No6Retailer pageldlc.com/en/product/PB00647659.htmlRead 15 October 2026LED RGB: No. The listing is for the white unit.

Dimensions and weight

1 of 2 differ

DimensionsiBody without cables. Width and height are the back face with the AC inlet. Depth is the length into the case, which decides case fit.

Width150Height86Depth140mm(5.9 × 3.4 × 5.5 in)1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026Specifications tab: Dimensions (LxWxH) 140 x 150 x 86 mm, so depth 140, width 150, height 86. Tom's Hardware says the unit is 160 mm long. The maker value is stored and retailers copy it.

Width150Height86Depth140mm(5.9 × 3.4 × 5.5 in)3Retailer pageeshop.enzure.se/seasonic-focus-gx-850w-atx/cat-p/c/p1005013704Read 15 October 2026140 mm (L) x 150 mm (W) x 86 mm (H). Depth 140, width 150, height 86. Hardware Busters writes 150 x 85 x 140 mm.4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Technical specifications: 150 x 85 x 140 mm (W x H x D). The maker figure of 86 mm height is stored.6Retailer pageldlc.com/en/product/PB00647659.htmlRead 15 October 2026Height 86 mm, width 150 mm, length 140 mm.

WeightiWeight of the unit alone. Use the Hardware Busters figure on hwbusters.com when the maker states none, not a copy on another site. Maker weights that include cables or the box, such as Corsair's, and retailer packed weights are not stored. A net weight counts unless the maker says it includes the cables.

Not available

1.6kg(3.5 lb)4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Technical specifications: 1.60 kg (3.5 lb). The maker states no weight in the spec table that was readable. The review does not say whether it includes cables.

In the box

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In the boxiItems supplied with this exact model, verbatim. The AC power cord differs per region.

AC power cable, Mounting screws, Velcro-style cable straps, Cable ties, User manual7Reviewtomshardware.com/pc-components/power-supplies/montech-century-ii-gold-850w-atx-3-1-power-supply-reviewRead 14 October 2026In the Box: AC power cable, mounting screws, reusable Velcro-style cable straps, cable ties and a small user manual. Review published 7 September 2026.

User's manual, Power supply installation guide, Plastic cable ties, Velcro cable ties, 4x PSU mounting screws, PSU tester device, Power cord, Cloth bag containing PSU modular cables10Reviewalktech.co/articles/unboxing-overview-seasonic-focus-gx-atx-3.1-850w-power-supply-unitRead 15 October 2026Unboxing of the black 850W unit, article dated May 2, 2026. Accessories: a Steam gift code promotional leaflet, user's manual, power supply installation guide, plastic cable ties, Velcro cable ties, 4x PSU mounting screws, PSU tester device, power cord and a cloth bag containing the modular cables. The promotional leaflet is not stored. The sample came through the Singapore distributor, so the power cord can differ by region.

Links

Not compared

Product page

www.montechpc.com/century-ii-850w1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026

seasonic.com/focus-gx-atx-31Maker product pageseasonic.com/focus-gx-atx-3Read 15 October 2026Seasonic's site is blocked for agents, so the page text was not read. The link is the FOCUS GX ATX 3.1 family page that search results and a review name for this unit. The specs come from Seasonic's launch release, a retailer copy of Seasonic's spec table, the 80 PLUS list and reviews.

Spec sheet

Not available

Not available

Manual

Not available

Not available

EPREL registration numberiId in the EU energy label database. Each size or model of a series has its own id, so it is per variant.

Not available

Not available

Warranty

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Manufacturer warranty (source market)iThe maker's warranty period for the exact SKU or configuration and market named in the source note. It applies only to that stated market, not every regional variant. Statutory consumer rights are excluded. The base term is stored. An extension that needs registration goes in the source note.

10years1Maker product pagemontechpc.com/century-ii-850wRead 14 October 2026Specifications tab: Warranty 10 Years. The page is the global maker page and names no market.

10years2Press releasethefpsreview.com/2024/09/30/seasonic-launches-focus-2024-series-atx-3-1-power-supplies-with-optisink-technology-and-other-design-innovationsRead 15 October 2026Key features: 10 years warranty. The release is global.3Retailer pageeshop.enzure.se/seasonic-focus-gx-850w-atx/cat-p/c/p1005013704Read 15 October 2026Warranty 10 Years.4Reviewhwbusters.com/psus/seasonic-focus-gx-850-v4-atx-v3-1-psu-reviewRead 15 October 2026Technical specifications: Warranty 10 years.

Both are also in the API. Back to all power supplies.