Introduction
Component heavyweight Corsair periodically updates its range of power-supply units (PSUs) to incorporate new features and technology. It has been three years since the popular RMx line had a makeover, and Corsair believes there is enough new to warrant a range update.
As before, five sensible capacities ply the range - 550W, 650W, 750W, 850W, 1,000W - and certification stays at 80 PLUS Gold. Let's focus on what is new.
Harnessing Corsair's ever-expanding fan range, the first meaningful change sees the 2018 model's rifle-bearing 135mm NR135L fan replaced by a 140mm magnetic levitation NR140ML spinner. This is a proper upgrade that ought to provide quieter operation and better longevity. On our 850W model it remains off until around 320W, and then rises smoothly up to full capacity, running at around 1,200rpm.
Corsair changes the grille design between generations, too, and we think it now looks better. Measuring 150mm wide, 86mm high and 160mm deep, there shouldn't be installation issues in any decent chassis. Build quality is good.
Keeping up with standards, the RMx 2021 is compatible with Microsoft's Modern Standby - S0 power state, ATX v2.51 minimum - enabling the computer to wake from sleep more quickly than legacy S3. There's nothing flashy about the exterior but that's no bad thing. No RGB, no fan lights, nothing.
Corsair continues teaming up with Channel Well Technology (CWT) to produce platforms based on its desired specifications. Between generations, CWT manages to increase the overall efficiency to the top-end of the 80 PLUS Gold range, going by specifications.
The RMx line has a deserved reputation for premium ripple suppression. For this reason, Corsair adds cable-integrated capacitors to the main ATX, CPU and PCIe cables.
We find it curious that Corsair bundles three 8-pin CPU cables for this 850W model. Very few boards demand this level of power - AMD Ryzen Threadripper, mostly - so it's more of a keeping-the-bases covered kind of move than of current practical value. It actually makes more sense on the 1,000W model, which also has a trio of CPU plugs.
As you can see, the trio can be plumbed in concurrently, alongside two runs of dual 6+2-pin PCIe for a couple of high-powered graphics cards. Having a total of 14 SATA feels overkill in 2021, though.
Corsair continues with a single 12V rail and enables the entire capacity to be meted out at an ambient 50°C.
Backed by the usual 10-year warranty and costing £130 at retailers, it's shame that, unlike previous generations, it is not yet available in white. So far, so good. Let's now roll the benchmark numbers.