Power supplies / Compare

Montech Century II 850W vs Seasonic CORE GX-750 (2024)

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Product A: Montech

Century II 850W

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B

Product B: Seasonic

CORE GX-750 (2024)

55 of 66 known

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Only differences

AMontech Century II 850W

BSeasonic CORE GX-750 (2024)

General

7 of 12 differ

Series

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

CORE GX2Press releasefunkykit.com/news/seasonic-launches-updated-core-atx-3-psu-series-with-atx-3-1-and-pcie-gen-5-1Read 15 October 2026The release calls the family the CORE GX ATX 3 series, in four outputs from 1000 W to 650 W.

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-CGX751-A5A32SF, SRP-CGX751-A5A32SF-W3Retailer pageonline.westech.sk/seasonic-core-gx-gold-750w-v2-atx-3-1-pcie-5-1-modular_d175947.htmlRead 15 October 2026Part No. SRP-CGX751-A5A32SF, the black unit. The white unit's number SRP-CGX751-A5A32SF-W comes from the AWD-IT listing.4Retailer pageldlc.com/en/product/PB00657445.htmlRead 15 October 2026Model SRP-CGX751-A5A32SF, product name Seasonic CORE GX ATX 3 (2024) 750 W.5Retailer pageawd-it.co.uk/seasonic-core-gx-750-750w-atx-3-1-power-supply-white-srp-cgx751-a5a32sf-w.htmlRead 15 October 2026MPN SRP-CGX751-A5A32SF-W for the white CORE GX-750.

GTIN / EAN

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

4711173878469, 47111738787113Retailer pageonline.westech.sk/seasonic-core-gx-gold-750w-v2-atx-3-1-pcie-5-1-modular_d175947.htmlRead 15 October 2026EAN 4711173878469 for SRP-CGX751-A5A32SF (black). The check digit is valid. The page says WESTech no longer sells the unit, which is a statement about that shop's range.5Retailer pageawd-it.co.uk/seasonic-core-gx-750-750w-atx-3-1-power-supply-white-srp-cgx751-a5a32sf-w.htmlRead 15 October 2026EAN 4711173878711 for SRP-CGX751-A5A32SF-W (white). The check digit is valid. The listing's Non-Modular line contradicts Seasonic, Cybenetics and every other source, so it is ignored.

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).

6 December 20242Press releasefunkykit.com/news/seasonic-launches-updated-core-atx-3-psu-series-with-atx-3-1-and-pcie-gen-5-1Read 15 October 2026Press release dated December 6, 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.

Available4Retailer pageldlc.com/en/product/PB00657445.htmlRead 15 October 2026The French shop's page shows the unit in stock in October 2026.5Retailer pageawd-it.co.uk/seasonic-core-gx-750-750w-atx-3-1-power-supply-white-srp-cgx751-a5a32sf-w.htmlRead 15 October 2026UK retailer listing shows the white unit in stock, fewer than 3 available, in October 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 $99.992Press releasefunkykit.com/news/seasonic-launches-updated-core-atx-3-psu-series-with-atx-3-1-and-pcie-gen-5-1Read 15 October 20265Retailer pageawd-it.co.uk/seasonic-core-gx-750-750w-atx-3-1-power-supply-white-srp-cgx751-a5a32sf-w.htmlRead 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 €115.92Press releasefunkykit.com/news/seasonic-launches-updated-core-atx-3-psu-series-with-atx-3-1-and-pcie-gen-5-1Read 15 October 20265Retailer pageawd-it.co.uk/seasonic-core-gx-750-750w-atx-3-1-power-supply-white-srp-cgx751-a5a32sf-w.htmlRead 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 releasefunkykit.com/news/seasonic-launches-updated-core-atx-3-psu-series-with-atx-3-1-and-pcie-gen-5-1Read 15 October 2026The release lists a USA price and an EU price for the black unit and a rest of the world price that names no country. Only US and EU are stored.

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 releasefunkykit.com/news/seasonic-launches-updated-core-atx-3-psu-series-with-atx-3-1-and-pcie-gen-5-1Read 15 October 2026Available in black and white.

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 pageonline.westech.sk/seasonic-core-gx-gold-750w-v2-atx-3-1-pcie-5-1-modular_d175947.htmlRead 15 October 2026The page copies Seasonic's spec table. Form Factor ATX/EPS, 140 x 150 x 86 mm, which is the ATX back face of 150 x 86 mm.8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026DUT Information: Type ATX12V.

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 releasefunkykit.com/news/seasonic-launches-updated-core-atx-3-psu-series-with-atx-3-1-and-pcie-gen-5-1Read 15 October 2026The units comply with the latest ATX 3.1 and PCIe Gen 5.1 standards.

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 releasefunkykit.com/news/seasonic-launches-updated-core-atx-3-psu-series-with-atx-3-1-and-pcie-gen-5-1Read 15 October 2026The units comply with PCIe Gen 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 releasefunkykit.com/news/seasonic-launches-updated-core-atx-3-psu-series-with-atx-3-1-and-pcie-gen-5-1Read 15 October 202680 Plus Gold certified units with a fully modular design and color-matching cables with a braided pattern.4Retailer pageldlc.com/en/product/PB00657445.htmlRead 15 October 2026Modularity: 100% modular.8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026DUT Information: Cable Design Fully Modular.

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.

Seasonic8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026DUT Information and Parts Description: OEM/ODM Seasonic.

Power

3 of 9 differ

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.

750W3Retailer pageonline.westech.sk/seasonic-core-gx-gold-750w-v2-atx-3-1-pcie-5-1-modular_d175947.htmlRead 15 October 2026Total continuous power 750 W.8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026DUT Information: Rated Power 750 W. The Power Specifications table gives a total maximum power of 750 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.

40°C3Retailer pageonline.westech.sk/seasonic-core-gx-gold-750w-v2-atx-3-1-pcie-5-1-modular_d175947.htmlRead 15 October 2026Operating Temperature 0 - 50 C, with derating from 100 % to 80 % linearly from 40 C to 50 C. Full power is therefore rated up to 40 C.

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 rail6Reviewgeeknetic.es/Review/3008/Seasonic-CORE-ATX-3-GX-750-Review.htmlRead 15 October 2026Spec list: Numero de railes: 1 de 12v.8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Power Specifications table lists one +12V column, 62A.

+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

62A3Retailer pageonline.westech.sk/seasonic-core-gx-gold-750w-v2-atx-3-1-pcie-5-1-modular_d175947.htmlRead 15 October 2026DC output: +3.3 V 20 A, +5 V 20 A, +12 V 62 A, -12 V 0.3 A, +5 VSB 3 A.8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Power Specifications table: +12V 62 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

744W3Retailer pageonline.westech.sk/seasonic-core-gx-gold-750w-v2-atx-3-1-pcie-5-1-modular_d175947.htmlRead 15 October 2026Maximum power row: 100 W, 744 W, 3.6 W and 15 W, with total continuous power 750 W. The 744 W is the +12V figure.8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Power Specifications table: +12V 744 W, total maximum power 750 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

100W3Retailer pageonline.westech.sk/seasonic-core-gx-gold-750w-v2-atx-3-1-pcie-5-1-modular_d175947.htmlRead 15 October 2026Maximum power row prints 100 W once for the +3.3 V and +5 V rails, so it is one shared limit.8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Power Specifications table: one merged cell of 100 W under +3.3V and +5V, so it is one shared limit. Each rail is 20 A.

+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 pageonline.westech.sk/seasonic-core-gx-gold-750w-v2-atx-3-1-pcie-5-1-modular_d175947.htmlRead 15 October 2026DC output: +5 VSB 3 A.8Measurementcybenetics.com/evaluations/psus/2753Read 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 pageonline.westech.sk/seasonic-core-gx-gold-750w-v2-atx-3-1-pcie-5-1-modular_d175947.htmlRead 15 October 2026AC input 100 V - 240 V, 10 - 5 A, 50 Hz - 60 Hz.8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026DUT Information: Rated Voltage 100-240 Vrms, manufacturer-provided.

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.

Yes8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Temperature and Compliance Info: ALPM (Alternative Low Power Mode) compatible, checked. ATX v3.1 PSU Power Excursion is also checked. The ATX 3.1 badge on the report reads Outside Validation Scope.

Certifications

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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 Gold9Certification listclearesult.com/80plus/sites/80plus/files/manufacturer-certificate/SEA%20SONIC%20ELECTRONICS%20CO.%20LTD._SRP-CGX751-A5A32SF_750W_SOCE%207567_Report_0.pdfRead 15 October 202680 PLUS list entry ID 7567, model SRP-CGX751-A5A32SF, 750W, 80 PLUS Gold, tested 9/24/2024 at 115V nominal and 60 Hz (typical efficiency at 50% load 91.51%). It matches Seasonic's claim of 80 PLUS Gold.

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 Platinum8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Report 25PS2753A, certification ID 252753, tested Feb 26, 2025 and issued Mar 6, 2025. ETA Platinum at 115V (badge image). Seasonic's retail listings print Cybenetics levels as TBA and 80 PLUS Gold.

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 Platinum8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026ETA Platinum at 230V (badge image).

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-8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026LAMBDA A- at 115V (badge image). The measured average of 29.84 dBA fits A-.

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-8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026LAMBDA A- at 230V (badge image). The measured average at 230V is 29.82 dBA.

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.

89.208%8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Average over more than 1450 load combinations at 115V. Ambient 28-32 C. Sample received Feb 11, 2025.

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.

91.222%8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Average over more than 1450 load combinations at 230V.

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.

70.718%8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Efficiency at 2% load at 115V. The unit is above 500 W, so the 2% load applies. At 230V it is 71.308%.

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.

0.9778Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Average over more than 1450 load combinations at 115V. At 230V it is 0.935.

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.

29.84dB(A)8Measurementcybenetics.com/evaluations/psus/2753Read 15 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 29.82 dBA.

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.

42.3dB(A)8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Typical load tests at 115V, 100% load row: 42.3 dB(A) at 1583 rpm fan speed, intake 45.48 C and exhaust 57.56 C. The fan runs at all loads on this unit.

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.

0.0749W8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Standby power consumption at 115V with no load on +5VSB. At 230V it is 0.1753 W.

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.

15.9ms8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Hold-Up Time and PWR_OK Signal: hold-up time 15.9 ms, AC loss to PWR_OK 11.7 ms, at maximum continuous load. Report 2753.

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.

31.17mV8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Non-accredited. 12V ripple at full load at 115V. At 230V it is 32.07 mV.

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%.

1.13%8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Non-accredited. 12V load regulation at 115V. At 230V it is 1.13%.

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 CORE GX-750 (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	750	16AWG	Not available
PCIe 8-pin (6+2)	2	1	700	16-18AWG	Not available
12V-2x6	1	1	700	16AWG	600
SATA power	6	2	455	18AWG	Not available
4-pin Molex	3	1	455	18AWG	Not available

Source4Retailer pageldlc.com/en/product/PB00657445.htmlRead 15 October 2026Connector rows: 2x +12V (P8 - 2 x P4), 6x Serial ATA, 1x ATX 20+4 pin, 3x Molex 4 pin, 2x PCI Express 6+2 pin, 1x PCI Express 16 pin (12V-2x6). These are the plug counts that the stored table uses.6Reviewgeeknetic.es/Review/3008/Seasonic-CORE-ATX-3-GX-750-Review.htmlRead 15 October 2026The set holds a 610 mm ATX cable, two 750 mm EPS cables, the 12V-2x6 cable, a cable that turns the 12V-2x6 connector into two 8-pin PEG plugs with the same 600 W limit, two SATA cables with up to 3 connectors and a 750 mm maximum length, and one Molex cable with three connectors and a 690 mm maximum length. The SATA and Molex lengths run to the last plug.7Reviewkitguru.net/components/power-supplies/zardon/seasonic-core-gx-850-atx-3-reviewRead 15 October 2026Page 2 of KitGuru's CORE GX 850 review shows Seasonic's Cable Summary slide for the whole CORE GX ATX 3 family, with one column per output. The 750 W column reads: MB 610 mm 1 cable with 20+4 pins, CPU 750 mm 2 cables with 4+4 pins, 12V-2x6 700 mm 1 cable, PCIe 750 mm with 6+2 pins 0 cables, PCIe 700 mm with 16 pins to 2 x 6+2 pins 1 cable, SATA 750 mm 2 cables with 3 connectors, Molex 690 mm 1 cable with 3 connectors. The slide has no single 6+2 pin PCIe cable for the 750 W unit, so the unit has 2 PCIe 8-pin plugs on 1 cable. The Cybenetics sample lists one more single 6+2 pin cable at 750 mm, which is not stored. Cable lengths to the first plug come from the Cybenetics report for SATA and Molex, since the slide gives lengths to the last plug. The 16-pin to dual 8-pin cable shares the 12V-2x6 PSU socket with the native 12V-2x6 cable on the 850 W unit, as the page 3 photo of the modular panel shows. The same panel is expected here, but no photo of the 750 W unit confirms it.8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Cables and Connectors table: ATX 615 mm 16-18AWG, EPS 4+4 750 mm 16AWG (2 cables), 2x 6+2 PCIe 700 mm on one cable with two plugs 16-18AWG, a single 6+2 PCIe 750 mm cable 16-18AWG, 12+4 pin PCIe 700 mm (600W) 16-28AWG, SATA 455 mm then 155 mm then 155 mm on 2 cables (6 plugs, 18AWG), 4-pin Molex 455 mm then 125 mm then 125 mm on 1 cable (3 plugs, 18AWG). The stored ATX, EPS and 12V-2x6 lengths and the PCIe cable follow Seasonic's cable slide. The 16-28AWG range of the 12V-2x6 cable includes the thin sideband wires, so the 16AWG power wire gauge is stored. The extra single 6+2 pin cable in the sample is not in Seasonic's slide.

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

2=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

6=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 pageonline.westech.sk/seasonic-core-gx-gold-750w-v2-atx-3-1-pcie-5-1-modular_d175947.htmlRead 15 October 2026Cable type: Individual Black Cables with Braided Pattern.6Reviewgeeknetic.es/Review/3008/Seasonic-CORE-ATX-3-GX-750-Review.htmlRead 15 October 2026The cables have individual sleeving of a plastic material with a textured finish like nylon braid, and the same sleeving goes on every cable.

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.

120mm2Press releasefunkykit.com/news/seasonic-launches-updated-core-atx-3-psu-series-with-atx-3-1-and-pcie-gen-5-1Read 15 October 2026A 120 mm hydro dynamic bearing fan with Seasonic's Smart and Silent Fan Control.3Retailer pageonline.westech.sk/seasonic-core-gx-gold-750w-v2-atx-3-1-pcie-5-1-modular_d175947.htmlRead 15 October 2026Fan Size 120 mm, Fan Control Smart and Silent Fan Control, life expectancy 25,000 hours at 40 C.8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Parts Description: Hong Hua HA1225H12F-Z, 120 mm.

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).

Hydrodynamic (HDB)2Press releasefunkykit.com/news/seasonic-launches-updated-core-atx-3-psu-series-with-atx-3-1-and-pcie-gen-5-1Read 15 October 2026Hydro dynamic bearing fan, 120 mm.3Retailer pageonline.westech.sk/seasonic-core-gx-gold-750w-v2-atx-3-1-pcie-5-1-modular_d175947.htmlRead 15 October 2026Fan Bearing: Hydro Dynamic Bearing.8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Parts Description: Hong Hua HA1225H12F-Z, 120 mm, 12V, 0.58A, Fluid Dynamic Bearing Fan. Seasonic's own wording is Hydro Dynamic Bearing.

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).

Always on6Reviewgeeknetic.es/Review/3008/Seasonic-CORE-ATX-3-GX-750-Review.htmlRead 15 October 2026These models do not stop the fan at idle. It always runs under PWM control at about 40% PWM up to 60% load, with idle speeds of about 400 rpm. The review lists the lack of a hybrid fan stop as a negative.8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026DUT Information: Semi-Passive Operation not checked. The fan reads 864 rpm at 10% load.

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.

No6Reviewgeeknetic.es/Review/3008/Seasonic-CORE-ATX-3-GX-750-Review.htmlRead 15 October 2026The review describes no fan mode switch and no hybrid fan mode. The unit has no semi-passive mode to switch off.8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026DUT Information: Semi-Passive Operation not checked, so there is no mode to switch off.

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 pageonline.westech.sk/seasonic-core-gx-gold-750w-v2-atx-3-1-pcie-5-1-modular_d175947.htmlRead 15 October 2026Protection: OCP, OPP, OTP, SCP, OVP, UVP. NLO and SIP come from the Cybenetics protection tests.8Measurementcybenetics.com/evaluations/psus/2753Read 15 October 2026Protection Features (Manufacturer) lists OPP, OCP (+12V), OTP, SCP, surge protection and inrush current protection. Fan failure protection is not ticked. The protection tests tick NLO and show SIP: surge MOV, inrush NTC and bypass relay.

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.

Not available

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 pageonline.westech.sk/seasonic-core-gx-gold-750w-v2-atx-3-1-pcie-5-1-modular_d175947.htmlRead 15 October 2026MTBF at 25 C, excluding the fan: 100,000 hours.

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.

No4Retailer pageldlc.com/en/product/PB00657445.htmlRead 15 October 2026Spec row LED RGB: No.

Dimensions and weight

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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 pageonline.westech.sk/seasonic-core-gx-gold-750w-v2-atx-3-1-pcie-5-1-modular_d175947.htmlRead 15 October 2026140 mm (L) x 150 mm (W) x 86 mm (H). Depth 140, width 150, height 86. The page lists the Cybenetics levels as TBA, so those fields come from the Cybenetics report.4Retailer pageldlc.com/en/product/PB00657445.htmlRead 15 October 2026Height 86 mm, width 150 mm, length 140 mm.6Reviewgeeknetic.es/Review/3008/Seasonic-CORE-ATX-3-GX-750-Review.htmlRead 15 October 2026Spec list: 140 mm (L) x 150 mm (W) x 86 mm (H).

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

Not available

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.

Not available

Links

Not compared

Product page

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

seasonic.com/core-gx-atx-3-20241Maker product pageseasonic.com/core-gx-atx-3-2024Read 15 October 2026Seasonic's site is blocked for agents, so the page text was not read. The link is the CORE GX ATX 3.1 family page that search results name for this unit. The specs come from Seasonic's launch release, retailer copies of Seasonic's spec table, the cable slide Seasonic's own presentation shows in a KitGuru review, the 80 PLUS list, a review and the Cybenetics report.

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.

7years2Press releasefunkykit.com/news/seasonic-launches-updated-core-atx-3-psu-series-with-atx-3-1-and-pcie-gen-5-1Read 15 October 2026Sea Sonic's 7-year worldwide manufacturer's warranty.3Retailer pageonline.westech.sk/seasonic-core-gx-gold-750w-v2-atx-3-1-pcie-5-1-modular_d175947.htmlRead 15 October 2026Warranty 7 Years.

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