Cold Test Results

For the testing of PSUs, we are using high precision electronic loads with a maximum power draw of 2700 Watts, a Rigol DS5042M  40 MHz oscilloscope, an Extech 380803 power analyzer, two high precision UNI-T UT-325 digital thermometers, an Extech HD600 SPL meter, a self-designed hotbox and various other bits and parts. For a thorough explanation of our testing methodology and more details on our equipment, please refer to our How We Test PSUs - 2014 Pipeline post.

The latest revision of the TX-M series is certainly improved in terms of efficiency, yet it still fails to achieve >92% at half load with an input voltage of 230 VAC. This result, however, does not mean that the unit’s certifications are false, just that it received its efficiency rating with an input voltage of 110 VAC, under which the 80Plus directive is slightly more lenient.

This particular model’s efficiency certification can be viewed here. The vast majority of manufacturers submit their units for 110 VAC testing - only 5% of the 80Plus certified non-redundant PSUs have been tested with an input voltage of 230 VAC. The TX550 maintains a good average efficiency of 90.3% within its nominal load range (20% to 100% of the unit's capacity) but tends to favor medium-to-heavy loads, struggling when the load is lower than 200 Watts.

The thermal control scheme of the Corsair TX550M is very simplistic, with the fan adjusting its speed according to the internal temperature of the unit. As such, it manages to maintain very low noise levels while at room temperature and up to medium loads. At heavier loads, the fan will increase its speed, yet not overly so, maintaining audible but typically comfortable noise levels.

The Corsair TX550M PSU Hot Test Results
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  • t.s - Saturday, December 2, 2017 - link

    I mean, all the peripheral on your example is not something that will make the system spent, like 150W
  • 1_rick - Friday, December 1, 2017 - link

    Well, that makes something like this model overkill for a lot of people, then. Just as an example, I have a Corsair CX-430 PSU, an overclocked Ryzen 1600X, and a GTX 950. During a GPU stress test, it will pull a bit under 250 watts. CPU stress tests are somewhat lower--I think under 200W. It idles well under 100, and normal usage is probably 120-160W.
  • mjeffer - Friday, December 1, 2017 - link

    This is one of my annoyances whenever building a new system. It's really hard to find a high quality, low wattage PSU that would represent your true needs. Most major vendors only go budget on low wattage or it's impossible to find someone who's done a teardown to see if it is made with quality parts because reviews are usually only done on grossly overpowered PSUs
  • KAlmquist - Saturday, December 2, 2017 - link

    I've been happy with the Seasonic SSR-360GP, but sadly it appears to have been discontinued. I guess the Antec EarthWatts EA-380 is worth a look.
  • Manabu - Monday, December 18, 2017 - link

    It is getting harder and harder to find high quality low wattage PSUs with enough cables. I'm using 6 sata and 3 ide and 1 6-pin vga cable (gtx 650 ti). My overclocked system draws up to 250W (measured at the wall) with linpack AVX2 and Furmark, but more normal high load is like 150-175W. Thus I would want a 350W psu for a good margin and efficiency.

    Instead I had to buy a 450W 80+gold psu (electricity here is expensive and it runs 24h/d). Previously I used a 420W 80+ bronze psu for 6 years and before that a 400W 80+ psu for 5 years. Power ratings are creeping up, but at least efficiency too. Still, if power ratings continue to go up efficiency for my loads will go down.
  • jhapp - Friday, December 1, 2017 - link

    People need reliability, not 3D graphics. I always buy PNY/Quadro high resolution 2D cards which run about 10 watts per monitor. 3D video cards are expensive and energy wasting. Add them to the long list of things people don't need but think they do because of media hype, like hi-res tvs, or hybrid cars, ethanol, E85, smart phones, cell phones, ...
  • Jimios - Friday, December 1, 2017 - link

    I'd like to see you play a modern game with a 10W 2D Quadro.
  • MadAd - Friday, December 1, 2017 - link

    With CPUs providing basic graphics these days I dont think the average user would buy a 3d card unless they actually had an app demanding it, eg for me Planetside 2 wouldnt even work without a serious graphics card, otherwise I wouldnt bother and just use the onboard.
  • Dr. Swag - Friday, December 1, 2017 - link

    But if you want to play video games...
  • LukaP - Friday, December 1, 2017 - link

    Even if you dont, iGPUs exist, on both sides...

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