Power supplies / Compare
CORSAIR RM850x (2024) vs Seasonic CORE GX-850 (2024)
Product A: CORSAIR
52 of 66 known
Change CORSAIR RM850x (2024)
Compare the Seasonic CORE GX-850 (2024) with
Product B: Seasonic
56 of 66 known
Change Seasonic CORE GX-850 (2024)
Compare the CORSAIR RM850x (2024) with
39 of 58 fields differ
- 30 different values
- 9 known for one only
- 16 the same
- 3 missing for both
Biggest differences
Each bar uses the scale of all 66 power supplies.
- Hold-up timeA: 25msB: 18msCORSAIR is 7 ms higher.
- SATA power connectorsA: 8B: 6CORSAIR has 2 more.
- Average noiseLower is betterA: 21.34dB(A)B: 28.17dB(A)CORSAIR is 6.83 dB(A) lower.
- 12V rippleLower is betterA: 24.2mVB: 28.89mVCORSAIR is 4.69 mV lower.
Size, drawn to scale
Front and side.
- ACORSAIR: 150 × 86 mm
- BSeasonic: 150 × 86 mm
All 66 fields
Every value links to where we found it.


General
7 of 12 differ
Series
Model numbers
CP-9020270-NA, CP-9020270-EU, CP-9020270-UK1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026SKU CP-9020270-NA. The EU and UK units are CP-9020270-EU and CP-9020270-UK, listed on Corsair's German page and by UK retailers with the same Tech Specs. The Japan unit is CP-9020270-JP and is not stored.10Retailer pagescan.co.uk/products/850w-corsair-rmx-series-rm850x-black-fully-modular-cybenetics-gold-pcie-51-single-rail-140mm-fan-atxRead 14 October 2026Scan lists CP-9020270-UK.
SRP-CGX851-A5A32SF, SRP-CGX851-A5A32SF-W3Retailer pageeshop.enzure.se/seasonic-850w-seasonic-core-srp-cgx851-a5a32sf/cat-p/c/p1005186250Read 15 October 2026Article number SRP-CGX851-A5A32SF, the black unit.8Retailer pageldlc.com/en/product/PB00657446.htmlRead 15 October 2026Model SRP-CGX851-A5A32SF for the black Seasonic CORE GX ATX 3 (2024) 850 W. The page says the product was referenced on December 5, 2024.10Retailer pageparadigit.ie/seasonic-core-gx-atx3-1-white-850-w/21750146/productRead 15 October 2026Product number manufacturer SRP-CGX851-A5A32SF-W for the white unit.
GTIN / EAN
840006667506, 840006667445, 8400066675448Spec databasecomparateur-gamer.fr/prix/corsair-rm850x-2024-840006667445Read 14 October 2026EAN 840006667445 with reference CP-9020270-EU.9Retailer pageebay.com/p/22074154707Read 14 October 2026eBay product page for CP-9020270-NA shows UPC 0840006667506. This is the only source for the NA code. The check digit is valid.10Retailer pagescan.co.uk/products/850w-corsair-rmx-series-rm850x-black-fully-modular-cybenetics-gold-pcie-51-single-rail-140mm-fan-atxRead 14 October 2026Scan lists manufacturer code CP-9020270-UK with GTIN 840006667544.
4711173878476, 47111738787283Retailer pageeshop.enzure.se/seasonic-850w-seasonic-core-srp-cgx851-a5a32sf/cat-p/c/p1005186250Read 15 October 2026EAN 4711173878476 for SRP-CGX851-A5A32SF (black). The check digit is valid.9Retailer pagemultitronic.fi/en/products/4589683/seasonic-core-gx-850w--virtalahde--80-plus-goldRead 15 October 2026EAN 4711173878728, product colour white. The check digit is valid.
Announced
Status
Predecessor
Not available
Not available
Successor
Not available
Not available
Launch price (US)
$149.993Maker product pageweb.archive.org/web/20240913090852/https://www.corsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026Archived copy of the Corsair US page from 2024-09-13, three days after launch. It shows a regular price of 149.99 USD with no discount, excluding sales tax. Hardware Busters gives an MSRP of 150 USD excluding VAT. TweakTown prints 169.99 USD, which is the later list price on Corsair's page today.6Reviewhwbusters.com/psus/corsair-rm850x-atx-v3-1-psu-reviewRead 14 October 2026Technical specifications: MSRP (excluding VAT) 150 USD. Review published September 14, 2024.
From $129.992Press releasefunkykit.com/news/seasonic-launches-updated-core-atx-3-psu-series-with-atx-3-1-and-pcie-gen-5-1Read 15 October 20269Retailer pagemultitronic.fi/en/products/4589683/seasonic-core-gx-850w--virtalahde--80-plus-goldRead 15 October 202610Retailer pageparadigit.ie/seasonic-core-gx-atx3-1-white-850-w/21750146/productRead 15 October 2026
Launch price (EU)
Not available
From €129.92Press releasefunkykit.com/news/seasonic-launches-updated-core-atx-3-psu-series-with-atx-3-1-and-pcie-gen-5-1Read 15 October 20269Retailer pagemultitronic.fi/en/products/4589683/seasonic-core-gx-850w--virtalahde--80-plus-goldRead 15 October 202610Retailer pageparadigit.ie/seasonic-core-gx-atx3-1-white-850-w/21750146/productRead 15 October 2026
Colours
Not available
Form factor
ATX3Retailer pageeshop.enzure.se/seasonic-850w-seasonic-core-srp-cgx851-a5a32sf/cat-p/c/p1005186250Read 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.6Measurementcybenetics.com/evaluations/psus/2750Read 15 October 2026Type ATX12V.
ATX version
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.7Certification listclearesult.com/80plus/sites/80plus/files/manufacturer-certificate/SEA%20SONIC%20ELECTRONICS%20CO.%20LTD._SRP-CGX851-A5A32SF_850W_SOCE%207565_Report_0.pdfRead 15 October 2026The list names the form factor ATX 3.1.
PCIe CEM version
Modular cables
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.6Measurementcybenetics.com/evaluations/psus/2750Read 15 October 2026Cable Design Fully Modular.
Built by (OEM)
Channel Well Technology (CWT)5Measurementcybenetics.com/evaluations/psus/2399Read 14 October 2026DUT Information: OEM/ODM Channel Well Technology. Parts description: Manufacturer (OEM) CWT.6Reviewhwbusters.com/psus/corsair-rm850x-atx-v3-1-psu-reviewRead 14 October 2026Technical specifications: OEM Channel Well Technology (CWT).
Power
4 of 9 differ
Rated continuous power
Full power rated up to
50°C1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026Overview: 50 C continuous operating temperature. The press release rates the power output at a 50 C ambient temperature.4Press releasecorsair.com/newsroom/press-release/corsair-updates-popular-rmx-series-low-noise-power-supplies-with-atx-3-1-compliance-and-native-atx-12v-2x6-connectorRead 14 October 2026Rated power output at a 50 C ambient temperature.
40°C3Retailer pageeshop.enzure.se/seasonic-850w-seasonic-core-srp-cgx851-a5a32sf/cat-p/c/p1005186250Read 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.4Retailer pageinside-tech.co.uk/power-supplies-2/seasonic-core-gx-v4-850w-80-plus-gold-atx-3-1-modular-psu-with-120mm-fdb-fan-braided-cables-7-year-warranty-blackRead 15 October 2026Operating Temperature 0 - 50 C (derating from 100 % to 80 % from 40 C to 50 C linearly).
12V rail design
+12V max current
70.8A1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026Power table: +12V 70.8A, 849.6W, model RPS0197, part no. 75-005876.2Owner's manualcorsair.com/us/en/explorer/diy-builder/power-supply-units/corsair-rmx-seriesRead 14 October 2026RM850x power table: +12V 70.8A, 849.6W, model RPS0197.
70A3Retailer pageeshop.enzure.se/seasonic-850w-seasonic-core-srp-cgx851-a5a32sf/cat-p/c/p1005186250Read 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.5Reviewkitguru.net/components/power-supplies/zardon/seasonic-core-gx-850-atx-3-reviewRead 15 October 2026Page 3: the +12V rail can deliver 70 A and the +3.3V and +5V 20 A, for a total of 850 W.6Measurementcybenetics.com/evaluations/psus/2750Read 15 October 2026Power Specifications table: +12V 70 A.
+12V max power
849.6W1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026Power table: +12V 70.8A, 849.6W.2Owner's manualcorsair.com/us/en/explorer/diy-builder/power-supply-units/corsair-rmx-seriesRead 14 October 2026RM850x power table: +12V 70.8A, 849.6W.
840W4Retailer pageinside-tech.co.uk/power-supplies-2/seasonic-core-gx-v4-850w-80-plus-gold-atx-3-1-modular-psu-with-120mm-fdb-fan-braided-cables-7-year-warranty-blackRead 15 October 2026The page copies Seasonic's spec table. DC output maximum power: +12 V 840 W, with 100 W, 3.6 W and 15 W for the other rows. The listing text names the white version.6Measurementcybenetics.com/evaluations/psus/2750Read 15 October 2026Power Specifications table: +12V 840 W.
+3.3V and +5V combined power
150W1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026Power table: +3.3V 20A and +5V 20A with one 150W cell.2Owner's manualcorsair.com/us/en/explorer/diy-builder/power-supply-units/corsair-rmx-seriesRead 14 October 2026RM850x power table: +3.3V 20A and +5V 20A, 150W.
100W4Retailer pageinside-tech.co.uk/power-supplies-2/seasonic-core-gx-v4-850w-80-plus-gold-atx-3-1-modular-psu-with-120mm-fdb-fan-braided-cables-7-year-warranty-blackRead 15 October 2026Power output row prints 100 W once for the +3.3 V and +5 V rails, so it is one shared limit.6Measurementcybenetics.com/evaluations/psus/2750Read 15 October 2026Power Specifications table: one merged 100 W cell for 3.3V and 5V, 20 A each.
+5V standby current
3A1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026Power table: +5VSB 3A, 15W.2Owner's manualcorsair.com/us/en/explorer/diy-builder/power-supply-units/corsair-rmx-seriesRead 14 October 2026RM850x power table: +5Vsb 3A, 15W.
AC input voltage
Lowest100Highest240V1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026Power table: AC input 100-240V, input current 10A-5A, 47-63Hz.2Owner's manualcorsair.com/us/en/explorer/diy-builder/power-supply-units/corsair-rmx-seriesRead 14 October 2026Power table: AC input rating 100V-240V, input current 10A-5A, 47Hz-63Hz.
Lowest100Highest240V3Retailer pageeshop.enzure.se/seasonic-850w-seasonic-core-srp-cgx851-a5a32sf/cat-p/c/p1005186250Read 15 October 2026AC input 100 V - 240 V, 11 - 5.5 A, 50 Hz - 60 Hz.4Retailer pageinside-tech.co.uk/power-supplies-2/seasonic-core-gx-v4-850w-80-plus-gold-atx-3-1-modular-psu-with-120mm-fdb-fan-braided-cables-7-year-warranty-blackRead 15 October 2026AC input 100 V - 240 V, 11 - 5.5 A, 50 Hz - 60 Hz.6Measurementcybenetics.com/evaluations/psus/2750Read 15 October 2026Manufacturer-provided information: 100-240 Vrms, 5.5-11 A, 50-60 Hz.
Alternative low power mode (ALPM)
Yes1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026Tech Specs: Modern Standby Yes. The Cybenetics report ticks ALPM compatible.5Measurementcybenetics.com/evaluations/psus/2399Read 14 October 2026Temperature and Compliance Info: ALPM (Alternative Low Power Mode) compatible, checked.
Certifications
5 of 5 differ
Cybenetics efficiency at 115V
Cybenetics efficiency at 230V
Cybenetics noise at 115V
A1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026Tech Specs: Cybenetics Noise A, with no input voltage. The Cybenetics report shows A at both voltages. The launch press release says A+, which the report does not show.5Measurementcybenetics.com/evaluations/psus/2399Read 14 October 2026The LAMBDA badge shows A at 115V.
Cybenetics noise at 230V
A1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026Tech Specs: Cybenetics Noise A, with no input voltage. The Cybenetics report shows A at both voltages.5Measurementcybenetics.com/evaluations/psus/2399Read 14 October 2026The LAMBDA badge shows A at 230V.
Measured
10 of 10 differ
Average efficiency at 115V (measured)
Average efficiency at 230V (measured)
Light-load efficiency at 115V (measured)
Average power factor at 115V (measured)
Average noise at 115V (measured)
Noise at full load at 115V (measured)
Standby power with no load at 115V (measured)
Hold-up time (measured)
12V ripple at full load (measured)
12V load regulation (measured)
Cables and connectors
3 of 7 differ
Cables
ACORSAIR RM850x (2024)
| Connector | Connectors | Cables | Length to first plug (mm) | Wire gauge | Rated power (W) |
|---|---|---|---|---|---|
| ATX 24-pin (20+4) | 1 | 1 | 610 | 16-20AWG | Not available |
| CPU 8-pin (EPS, 4+4) | 2 | 2 | 750 | 18AWG | Not available |
| PCIe 8-pin (6+2) | 3 | 3 | 650 | 16-18AWG | Not available |
| 12V-2x6 | 1 | 1 | 650 | Not available | 600 |
| SATA power | 8 | 2 | 505 | 18AWG | Not available |
| 4-pin Molex | 3 | 1 | 550 | 18AWG | Not available |
Source1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026Cable listing: 1 ATX 24-pin 610 mm, 2 EPS 8-pin (4+4) 750 mm, 1 PCIe 12V-2x6 (12+4) 650 mm, 3 PCIe 8-pin (6+2) 650 mm, 2 SATA cables with 4 plugs each (505 mm to the first plug, 115 mm spacing, 850 mm total), 1 PATA cable with 3 plugs (550 mm to the first plug, 100 mm spacing, 750 mm total). All lengths have a tolerance of 10 mm, the PATA cable 25 mm. PATA plugs are the 4-pin Molex plugs. The page does not rate the 12V-2x6 cable. The Cybenetics report and Hardware Busters list it at 600 W. Gauges come from the Cybenetics report. The 16-24AWG range for the 12V-2x6 cable includes the thin sideband wires, so no gauge is stored for it. Cybenetics lists the SATA cable at 500 mm, which is not stored.2Owner's manualcorsair.com/us/en/explorer/diy-builder/power-supply-units/corsair-rmx-seriesRead 14 October 2026Included cables: 1x ATX 24-pin 610 mm, 2x EPS 8-pin (4+4) 750 mm, 1x PCIe 12V-2x6 (12+4) 650 mm, 3x PCIe 8-pin (6+2) 650 mm, 2x SATA with 4 plugs 850 mm, 1x PATA with 3 plugs 750 mm.5Measurementcybenetics.com/evaluations/psus/2399Read 14 October 2026Cables and Connectors table: ATX 16-20AWG, EPS 18AWG, 6+2 pin PCIe 16-18AWG, 12+2 pin PCIe (600W) 16-24AWG, SATA 18AWG and Molex 18AWG, no in-cable capacitors. The 12V-2x6 cable is listed at 650 mm.
BSeasonic CORE 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 | 750 | 16AWG | Not available |
| PCIe 8-pin (6+2) | 1 | 1 | 750 | 16-18AWG | 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 |
Source5Reviewkitguru.net/components/power-supplies/zardon/seasonic-core-gx-850-atx-3-reviewRead 15 October 2026Page 2 shows Seasonic's Cable Summary slide for the CORE GX ATX 3, 850 W column: 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 1 cable with 6+2 pins, PCIe 700 mm 1 cable with 16 pins to 2 x 6+2 pins, SATA 750 mm 2 cables with 3 connectors, Molex 690 mm 1 cable with 3 connectors. The review says both connector types support up to 600 W. The SATA and Molex lengths run to the last plug, so the first-plug lengths come from the Cybenetics report (455 mm for both). The page 3 photo of the modular panel shows one 12-pin PCIe socket, so the 16-pin to dual 8-pin cable shares that socket with the native 12V-2x6 cable. Wire gauges come from Cybenetics.6Measurementcybenetics.com/evaluations/psus/2750Read 15 October 2026Cables and Connectors table: ATX 20+4 pin 620 mm 16-18AWG, 2 x 4+4 pin EPS12V 750 mm 16AWG, one cable with 2 x 6+2 pin PCIe plugs 710 mm 16-18AWG, one 6+2 pin PCIe 750 mm 16-18AWG, 12+4 pin PCIe 700 mm (600W) 16-28AWG, 2 SATA cables of 455+155+155 mm with 6 plugs, one 4-pin Molex cable of 455+125+125 mm with 3 plugs, 18AWG, no in-cable capacitors. The 16-28AWG range of the 12V-2x6 cable includes the thin sideband wires, so the stored gauge is the 16AWG power wire. Seasonic's slide lengths are stored where they are first-plug lengths. Cybenetics measured 620 mm for the 24-pin cable and 710 mm for the dual 8-pin cable.8Retailer pageldlc.com/en/product/PB00657446.htmlRead 15 October 2026Power connectors: 2 x +12V (P8, 2 x P4), 6 x Serial ATA, 1 x ATX 20+4 pin, 3 x Molex (4 pin), 3 x PCI Express 6+2 pin, 1 x PCI Express 16 pin (12V-2x6).
CPU (EPS) connectors
2
2
PCIe 8-pin connectors
3
3
16-pin GPU connectors
1
1
SATA power connectors
8
6
4-pin Molex connectors
3
3
Cable style
Embossed or debossed flat1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026Cable listing: Cable Type Embossed for every cable. The Tech Specs row says Type 4.4Press releasecorsair.com/newsroom/press-release/corsair-updates-popular-rmx-series-low-noise-power-supplies-with-atx-3-1-compliance-and-native-atx-12v-2x6-connectorRead 14 October 2026Fully modular, embossed, ultra-flexible cables.6Reviewhwbusters.com/psus/corsair-rm850x-atx-v3-1-psu-reviewRead 14 October 2026Cables page: all cables are embossed.
Sleeved3Retailer pageeshop.enzure.se/seasonic-850w-seasonic-core-srp-cgx851-a5a32sf/cat-p/c/p1005186250Read 15 October 2026Cable type: Individual Black Cables with Braided Pattern.5Reviewkitguru.net/components/power-supplies/zardon/seasonic-core-gx-850-atx-3-reviewRead 15 October 2026The cables are individually braided.
Fan
4 of 4 differ
Fan size
140mm1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026Overview: 140mm low-noise fan.4Press releasecorsair.com/newsroom/press-release/corsair-updates-popular-rmx-series-low-noise-power-supplies-with-atx-3-1-compliance-and-native-atx-12v-2x6-connectorRead 14 October 2026140mm fan.5Measurementcybenetics.com/evaluations/psus/2399Read 14 October 2026Cooling: 140mm Fluid Dynamic Bearing Fan (NR140HP), 12V, 0.33A.
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 pageeshop.enzure.se/seasonic-850w-seasonic-core-srp-cgx851-a5a32sf/cat-p/c/p1005186250Read 15 October 2026Fan Size 120 mm, Fan Control Smart and Silent Fan Control, life expectancy 25,000 hours at 40 C.5Reviewkitguru.net/components/power-supplies/zardon/seasonic-core-gx-850-atx-3-reviewRead 15 October 2026Page 4: Hong Hua 120 mm Hydro (Fluid) Dynamic Bearing fan, 12 V, 0.58 A, up to 2,200 rpm, model HA1225H12F-Z.6Measurementcybenetics.com/evaluations/psus/2750Read 15 October 2026Fan Hong Hua HA1225H12F-Z, 120 mm.
Fan bearing
Fluid dynamic (FDB)1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026Overview: a fluid dynamic bearing fan with magnetic dome structure. The Cybenetics report lists a Fluid Dynamic Bearing fan. The bearing is stored as fluid dynamic, since the maker names the dome as a structure of the fan and not as the bearing.4Press releasecorsair.com/newsroom/press-release/corsair-updates-popular-rmx-series-low-noise-power-supplies-with-atx-3-1-compliance-and-native-atx-12v-2x6-connectorRead 14 October 2026140mm fluid-dynamic bearing (FDB) fan.5Measurementcybenetics.com/evaluations/psus/2399Read 14 October 2026Cooling: Fluid Dynamic Bearing fan.
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 pageeshop.enzure.se/seasonic-850w-seasonic-core-srp-cgx851-a5a32sf/cat-p/c/p1005186250Read 15 October 2026Fan Bearing: Hydro Dynamic Bearing.5Reviewkitguru.net/components/power-supplies/zardon/seasonic-core-gx-850-atx-3-reviewRead 15 October 2026Page 4: Hong Hua 120mm Hydro (Fluid) Dynamic Bearing (HDB).6Measurementcybenetics.com/evaluations/psus/2750Read 15 October 2026Fan Hong Hua HA1225H12F-Z, 120 mm, 12 V, 0.58 A, listed as a Fluid Dynamic Bearing fan. Seasonic names it a Hydro Dynamic Bearing.
Fan mode
Semi-passive1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026Tech Specs: Zero RPM Mode Yes. The fan is off at low to medium loads.5Measurementcybenetics.com/evaluations/psus/2399Read 14 October 2026Semi-Passive Operation checked and selectable.
Always on5Reviewkitguru.net/components/power-supplies/zardon/seasonic-core-gx-850-atx-3-reviewRead 15 October 2026Page 3: no Hybrid fan control is offered with this unit. The fan spins very slowly at low power and the unit is not audible below about 650 W. Some retailers print a semi-fanless row. Quiet PC copies the same row for the 650, 750 and 850 W columns, even printing 850 W power output in the 650 W column, so it is not used.6Measurementcybenetics.com/evaluations/psus/2750Read 15 October 2026Semi-Passive Operation is not ticked. The typical load tests show 836 rpm at 10 percent load and 833 rpm at 20 percent, so the fan always spins.
Protection and parts
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Protections
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)2Owner's manualcorsair.com/us/en/explorer/diy-builder/power-supply-units/corsair-rmx-seriesRead 14 October 2026Protections section: OVP and UVP on 12V, 5V and 3.3V, OCP on 3.3V, 5V and 12V, OTP, SCP and OPP. The six maker protections are stored together with NLO and SIP from the Cybenetics tests.6Reviewhwbusters.com/psus/corsair-rm850x-atx-v3-1-psu-reviewRead 14 October 2026Protection Features page, which presents the Cybenetics protection tests: OCP, OPP, OTP, SCP, NLO, fan failure protection and SIP (surge MOV, inrush NTC thermistor and bypass relay) all shown. The page has no OVP or UVP row.
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-850w-seasonic-core-srp-cgx851-a5a32sf/cat-p/c/p1005186250Read 15 October 2026Protection: OPP, OCP, OTP, OVP, SCP, UVP.5Reviewkitguru.net/components/power-supplies/zardon/seasonic-core-gx-850-atx-3-reviewRead 15 October 2026Page 4: OPP, OVP, UVP, OCP, OTP and SCP.6Measurementcybenetics.com/evaluations/psus/2750Read 15 October 2026Protection Features (Manufacturer): OPP, +12V OCP, OTP, SCP, surge and inrush protection. The protection tests tick NLO and SIP (surge MOV, inrush NTC and bypass relay). Fan failure protection is not present. The report has no UVP row, so OVP and UVP come from the maker.
All-Japanese capacitors
Yes1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026Overview: 100% industrial-grade, 105 C rated Japanese electrolytic capacitors.4Press releasecorsair.com/newsroom/press-release/corsair-updates-popular-rmx-series-low-noise-power-supplies-with-atx-3-1-compliance-and-native-atx-12v-2x6-connectorRead 14 October 2026100% Japanese electrolytic capacitors.
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MTBF (claimed)
100,000h3Retailer pageeshop.enzure.se/seasonic-850w-seasonic-core-srp-cgx851-a5a32sf/cat-p/c/p1005186250Read 15 October 2026MTBF at 25 C, excluding the fan: 100,000 hours.4Retailer pageinside-tech.co.uk/power-supplies-2/seasonic-core-gx-v4-850w-80-plus-gold-atx-3-1-modular-psu-with-120mm-fdb-fan-braided-cables-7-year-warranty-blackRead 15 October 2026MTBF at 25 C, excl. fan 100,000 hours.
Monitoring and lighting
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Software monitoring
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Software
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Built-in power display
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RGB lighting
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Dimensions and weight
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Dimensions
Width150Height86Depth160mm(5.9 × 3.4 × 6.3 in)1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 14 October 2026Tech Specs: 160x150x86 with no unit. The manual gives length 160 mm, width 150 mm and height 86 mm. Depth is 160 mm.2Owner's manualcorsair.com/us/en/explorer/diy-builder/power-supply-units/corsair-rmx-seriesRead 14 October 2026RM850x specifications: length 160 mm, width 150 mm, height 86 mm.
Width150Height86Depth140mm(5.9 × 3.4 × 5.5 in)3Retailer pageeshop.enzure.se/seasonic-850w-seasonic-core-srp-cgx851-a5a32sf/cat-p/c/p1005186250Read 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.5Reviewkitguru.net/components/power-supplies/zardon/seasonic-core-gx-850-atx-3-reviewRead 15 October 2026Page 3: 140 mm x 150 mm x 86 mm.8Retailer pageldlc.com/en/product/PB00657446.htmlRead 15 October 2026Height 86 mm.
Weight
1.79kg(3.9 lb)6Reviewhwbusters.com/psus/corsair-rm850x-atx-v3-1-psu-reviewRead 14 October 2026Technical specifications: 1.79 kg (3.95 lb). Corsair's 3 kg figure is not stored, since it is most likely a packed weight.7Reviewigorslab.de/en/corsair-rm850x-atx-v3-1-power-supply-2024-testRead 14 October 2026Igor's Lab copy of the Hardware Busters review, published November 6, 2024. It lists 1.79 kg and 150 x 85 x 160 mm. The maker's 86 mm height is stored.
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In the box
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In the box
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Cable ties, Screws for mounting, Regional specific power cable, Literature5Reviewkitguru.net/components/power-supplies/zardon/seasonic-core-gx-850-atx-3-reviewRead 15 October 2026Page 2: the box contains some cable ties, screws for mounting, a regional specific power cable and some literature, with the cables set to one side. Review dated December 31, 2024.
Links
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Product page
www.corsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-na1Maker product pagecorsair.com/us/en/p/psu/cp-9020270-na/rmx-series-rm850x-fully-modular-power-supply-cp-9020270-naRead 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, a cable slide printed in a review, the 80 PLUS list and the Cybenetics report.
Spec sheet
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Manual
www.corsair.com/us/en/explorer/diy-builder/power-supply-units/corsair-rmx-series2Owner's manualcorsair.com/us/en/explorer/diy-builder/power-supply-units/corsair-rmx-seriesRead 14 October 2026
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EPREL registration number
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Warranty
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Manufacturer warranty (source 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 pageeshop.enzure.se/seasonic-850w-seasonic-core-srp-cgx851-a5a32sf/cat-p/c/p1005186250Read 15 October 2026Warranty 7 Years.5Reviewkitguru.net/components/power-supplies/zardon/seasonic-core-gx-850-atx-3-reviewRead 15 October 2026Closing page: the Core GX range comes with a 7 year warranty.
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