RM850x Shift White: Hands On Corsair’s Twisted Modular PSU
Modular cabling was supposed to make system configuration easier, but reaching those cable connectors on the back of an installed power supply has been far from easy. Corsair’s “Shift” series puts its connectors on the side, usually behind the right side-panel of the typical mid-tower. That same convenience would shift to the lower chamber PSU mount of our test platform, leaving us to question only whether the unit could satisfy our connectivity needs and efficiency desires. On to the test!
| RM850x Shift: Published Tech Specs (via Corsair web site) | |||
| Cybenetics Efficiency | Gold | PCIe Connector | 4 |
| Cybenetics Noise | A | Fan Size MM | 140mm |
| PATA Connector | 8 | Continuous Power W | 850 Watts |
| EPS Connector | 2 | ATX Connector | 1 |
| SATA Connector | 12 | ATX12V Version | 3.1 |
| Fan Bearing Technology | FDB | MTBF Hours | 100,000 hours |
| Modern Standby | Yes | 80 PLUS Efficiency | Gold |
| Dimensions | 160mm x 150mm x 86mm | Warranty | 10 Year |
| Cable Type | Type 5 | Weight | 3.3kg |
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Also available in Black, the RM850x Shift White arrived with a bundle of zip-ties, US-standard (NEMA 5-15) AC power, ATX/EPS 24-pin motherboard, two EPS12V/ATX12V splitable 8-pin/4-pin CPU power, three 8-pin/6-pin PCIe graphics card power, one 12V-2×6 (formerly 12VHPWR), three triple-drive SATA and two triple-drive ATA power cables.
Shown at inch scale, the main cables are 60 to 65cm long, the drive cables 46cm plus 95mm between its first, second, and third connectors.
Enthusiasts who fully appreciate how Nvidia’s 12VHPWR shrunk the size of its 600W interface will surely appreciation the similar pin design of the RM850x Shift’s miniature cable interfaces.
With its input power plug and switch pointing out the back of the case and its internal cable headers pointing toward its right side, there’s nothing but logos to see on the RM850x’s front end and left side.
Useful info from the label includes its CP-9020274 part-number (CP-9020252 for the black version) and its 70.8A rating for the +12V rail, allowing its full rated power to go to the CPU and/or graphics card.
Though the RM850w Shift is designed to operate at zero RPM under most loads, the 1200-1300 RPM fan that kicks in under high temperature scenarios merely pushes its noise level up from silent to quiet. Cybenetics says that it starts at 60% load (6dbA) and climbs as high at 35dbA at 110% load (10% over-capacity) when measured from 1m.
Inside we find a Channel Well Technology Active PFC design, with a half-bridge LLC resonant converter on the primary side feeding the 12V rail and through a synchronous rectifier. DC-DC converters on the 12V rail supply the 5V, 3.3V and 5V standby rails. To help the unit outlast its ten-year limited warranty, Nippon Chemi-Con, Nichicon and Rubycon capacitors are used throughout.
Here’s how its basic features stand up to other units vying for use as our motherboard test platform’s upgrade:
| Model | Corsair RM850x Shift (CP-9020274) | NZXT C850 SFX Gold (PS-2402) | ASRock SL-1200GW (90-UXS120-GFUABA) | Toughpower SFX Platinum (PS-STP-1000FNFAPU-1) | InWin P105II (IW-PS-PII1050W) | Sama P1200 (XPH1200-AP) |
| +12V Max (Amps) | 70.8A | 70.83A | 100A | 83.3A | 87.5A | 100A |
| 12V-2×6 | 1 | 1 | 2 | 1 | 1 | 2 |
| 6+2 Pin PCIe | 3 | 3 | 3 | 4 | 3 | 3 |
| EPS12V | 2 | 1 | 2 | 2 | 2 | 2 |
| 80Plus Cert. | Gold | Gold | Gold | Platinum | Platinum | Platinum |
| Weight | 1.68kg | 0.96kg | 1.87kg | 1.09kg | 1.70kg | 1.75kg |
| Depth | 160mm | 100mm | 150mm | 104mm | 150mm | 150mm |
| Warranty | 10-years | 10-years | 10-years | 7-years | 10-years | 10-years |
| Price | $170 | $170 | $160 | $180 | $170 | $160 |
And here’s the system we’ve used to test all these models:
| System Configuration | |
| CPU | Intel Core i9-13900K: 24C/32T, 3.0-5.8 GHz, 36 MB L3 Cache, LGA 1700, Locked at 5.0P/4.0E GHz, 1.25V Core |
| CPU Cooler | Alphacool Core 1 LT Aurora, Eisbecher D5 150mm, NexXxoS UT60 X-Flow 240mm |
| Motherboard | ASRock Z790 Taichi Carrara, BIOS 12.13 (04/23/2024) |
| RAM | Crucial Pro OC Gaming Edition DDR5-6400 32GB Kit |
| Graphics | ASRock RX 7700 XT Phantom Gaming 12GB OC 2276 MHz GPU, 2599 MHz Boost, GDDR6-18000 |
| System Drive | Crucial T700 PCIe Gen5 2TB M.2 SSD |
| Test Condition | |
| CPU Load | Prime95 v30.8 build 16 Torture Test, Small FFTs |
| GPU Load | Furmark 2.7.0.0 GL Test, 1920×1080 |
We’ve been relying heavily on Cybenetics reports for stress testing at and above the rated capacity of various models before we consider their suitability as a replacement for our test platform: Since our build can only reliably pull a continuous load up to approximately 735W, efficiency and applicability to that system have become primary considerations for that roll
It only uses a few more watts than its competition, but those few watts drive it down from the 91% efficiency seen in our top contenders to a mere 89%. On the other hand, being able to reach in the side and reconfigure cables without trying to shove a hand between the front of the power supply and the case’s integrated backplane surely adds convenience worthy of additional consideration.
| Corsair RM850x Shift (CP-9020274) | |
| Pros | Cons |
| Convenient side-access cable jacks | Some cases don’t have the ~30mm required side clearance. |
| The Verdict | |
| The RMX850x Shift’s namesake feature adds exceptional convenience to an otherwise unremarkable unit. | |
