Corsair VX550W PSU

Results

The 12V rail has been reeled back to "just" 41A compared to the TX750W’s 60A 12V rail, but the benefit of a single rail is that whichever cables you use you have the full 492W at your disposal. The 3.3V and 5V rails may also be the same 30A/28A as the TX750W’s rails, but they've also been scaled back to 140W overall rather than 180W, although you shouldn't need to use anywhere near the full 140W in a normal PC.

In its documentation on the VX550W, Corsair states that the fan noise is kept under a very quiet 22dB until you reach over 350W – we found this to be very true during testing at 50 percent load where it was virtually silent apart from a slight fan tick. The sides, base and exhaust air were cool to touch as well.

Jumping up to 75 percent load the noise jumped a bit but it was still very quiet and very tolerable – in any case you'd be very hard pressed to hear it above the noise of a hard drive unless you've buried it in concrete. The sides and base were still cool to touch, as was the exhausted air. Again though, the most noticeable thing was the fan tick which was now more of a whirr – on further inspection it was quite evident that the fan bearing was causing it, even though the fan itself was not vibrating out of sorts.

Finally at 100 percent load, after we left the unit to warm for a short while, the fan became really very noisy although the bearing whirr had now stopped. There was lots of air being drawn in but most was being bounced back out and very little being pushed out the back – this exhaust air was hot to the touch.

The performance in general was exceptional with solid rail performance, very high efficiencies of 85-86 percent and high PFC too. The only drop was when we loaded to 100 percent with a focus on the 3.3V and 5V rails – this dropped the efficiency down to a fraction below 80 percent. No PC will ever use that kind of weighting – we merely test to see if it does what it says on the tin here, and while the voltages are all green we have to knock the VX550W down just a touch for this result.

By looking back at the Thermaltake Toughpower Q-Fan 650W results we can see the similarities – that too dropped efficiency during 3.3V and 5V by a similar amount. The fact that Corsair drops a fraction more on an "over specified unit" leads us to believe that it cut back on other components elsewhere – how can it afford to charge £20 less than the Thermaltake otherwise?