The Corsair RM1000x SHIFT is a 1000W fully modular, ATX form factor, ATX 3.1 power supply. It offers a single hybrid fan mode and was launched with a MSRP of $209.99 USD. It is part of Corsair’s RMx SHIFT lineup, which features a distinctive design that repositions cable connections to the side, aligning them with the case’s side panel for easier access and streamlined cable management. This setup is particularly beneficial for users who prioritize clean builds and efficient cable routing. Corsair provides a list of compatible cases for the RMx SHIFT series, although this unit fits any ATX-compatible PC case with a minimum 210 mm width and at least 30 mm clearance on the connector side to ensure side access.
While the RM1000x SHIFT omits Under Voltage Protection (UVP) in favor of Catastrophic Failure Protection (CFP)—a basic feature not typically marketed as a selling point—its efficiency at low loads and resilience to brownouts make it a reliable choice for those seeking a dependable power supply.
WHAT YOU NEED TO KNOW
THE GOOD
- Cables
Equipped with a variety of flexible, flat cables using Corsair Type 5 Micro-Fit connectors.
- Resiliency
The RM1000x SHIFT is very resilient to brownouts, making it a reliable choice.
- Efficiency
Delivers excellent efficiency at low loads, maintaining strong efficiency at 115V even at low (2%) loads.
THE BAD
- Protections
Lacks UVP, relying instead on CFP, which should be a standard rather than a marketed feature.
THE REST
- Overall
While the RM1000x SHIFT didn’t perform exceptionally in every test, it still maintained good results overall. Its great efficiency at low loads and resilience to brownouts makes it a good recommendation for users needing a reliable power supply.
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The RM1000x SHIFT is designed in the ATX form factor, with its cable connections shifted to the longer side for ease of access and cable management. It is compatible with ATX-format cases, provided they meet the minimum width and clearance requirements outlined by Corsair. As a result of this unique design, the effective length listed here is identical to the length of the unit. However, the effective width is measured to be approximately 195 mm.
In the Box, the unit comes with minimal accessories, including Zip-Ties, mounting bolts, and user documentation. The included flexible, flat, cables feature Corsair’s Type 5 Micro-Fit connectors. On the box Corsair markets PCIe 5.0 compatibility, however they have since updated the included cables to be compatible with PCIe 5.1, and comes with a PCIe 5.1 12V-2x6 cable.
A 140 mm Fluid Dynamic Bearing fan provides effective cooling, while the power supply’s rating and specifications align well with its price range. We could not find the Operating Temperature of this power supply and cannot verify this through testing.
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Front of the box.
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Power input side of the PSU.
Top of the PSU displaying the fan.
Bottom of the PSU displaying the specifications.
| +12 V | +5 V | +3.3 V | +5 Vsb | -12 V | |
|---|---|---|---|---|---|
| CURRENT | 83.3 A | 20 A | 20 A | 3 A | N/A |
| WATTAGE | 1000 W | 150 W | 15 W | N/A | |
| 1000 W | |||||
Please note that the above ratings are manufacturer advertised specifications.
The RM1000x SHIFT offers a single hybrid fan mode, allowing the fan to remain off under light loads for quieter operating—a feature Corsair refers to as “Zero RPM” mode, which is not switchable.
In terms of protections, this unit does not come with the aforementioned UVP, but rather replaces it with CFP. The power supply is backed by a 10-year warranty.
In testing, the RM1000x SHIFT delivered respectable performance across most parameters. During load regulation testing, a 0.184 V drop on the 12V rail was observed at full power output. Although the 12V rail dipped below its nominal level at higher loads, it met general requirements across most rails, and this minor issue was not considered critical.
Voltage ripple was somewhat higher than competitors, with fully loaded ripple values on the 12V rail reaching 59 mV, while the 5V and 3.3V rails registered 38 mV and 51 mV respectively. While the 3.3V rail does reach a voltage ripple of 54 mV, this was at 110% load and ATX requirements don't apply. The maximum 3.3V rail voltage ripple measured within the rated range was 51 mV. While the unit withstood all of the excursions, it struggled to stay within ATX voltage limits during some of the quicker and higher load percentage excursions.
The RM1000x SHIFT does not have a -12V rail therefore there are no results for this rail.
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Rated at 80PLUS Gold, the RM1000x SHIFT performed well in efficiency benchmarks. It delivered particularly high efficiencies at low loads, where it achieved one of the highest efficiency at 115V 2% loads, and among the leaders at 230V. Efficiency dipped slightly to average levels at 10% load and above, which is typical of everyday operational scenarios.
Brownout tests indicated impressive stability, with the unit holding steady for 16 ms at both 115V and 230V inputs. Over Power Protection triggered at 126% of rated load, allowing the 12V rail to sustain 105 A, or 126% of its rating, which is in line with expectations for a power supply of this class.
