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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  • sweeper765 - Sunday, December 3, 2017 - link

    Using 8700k OC'ed, 2x8gb ddr4 1.35v, gtx 1060, 3 hdd, 2 ssd.
    I get 35-40 W idle and about 270W max load.
    So even 300W would be enough, though ideally for efficiency would be 550W. No need to go higher.
  • Oxford Guy - Saturday, December 9, 2017 - link

    The optimal range for total system power is just 300 watts with a top-tier card? Yeah, right.

    There are two other reasons to have extra capacity in a PSU:

    1) Capacitor aging

    2) Lower loads on higher spec units tend to be quieter.
  • Oxford Guy - Saturday, December 9, 2017 - link

    Another thing is that there are spikes in power usage. Sometimes transient spikes are quite a lot above the average power usage.
  • Manabu - Monday, December 18, 2017 - link

    1) Even with capacitor aging, there no need to buy a PSU more than double the max consumption of your system. So, a 300W PSU is indeed too low for a top-tier card, but a 550W one would already be more than enough. For my system with a mid-low range GPU with 250W max load (175W more normal high load) a 350W would also be plenty.

    2) There are platinum fanless 400W psus. Low wattage psus being noisier is just a reflect of this warped market that only valorizes high wattage psus. On the other hand, lower loads on higher wattage psus tend to be less efficient, so more heat in the ambient.
  • Alistair - Friday, December 1, 2017 - link

    No idle fan mode, no buy. This alone shows the cooling is poor, and the noise profile will be poor. Many other better choices. Shame Corsair for not including a standard feature nowadays.
  • Oxford Guy - Saturday, December 9, 2017 - link

    This site tends to not put enough emphasis on noise. However, at least it was the only one that called out Seasonic for its terrible performance in the 1050 model that could be "heard from rooms away".
  • Ken_g6 - Friday, December 1, 2017 - link

    Why should I buy a currently-$72 Corsair, when I can get either a $55 Seasonic FOCUS Plus after rebate, or a $60 Rosewill Capstone before rebate (other versions of which are an AnandTech Editor's Choice)?
  • oranos - Friday, December 1, 2017 - link

    hard to buy anything other than seasonic
  • airdrifting - Sunday, December 3, 2017 - link

    Again there are better quality power supply for less money. Every power supply recommendation article on Anandtech has been crap so far leading me to believe you guys are just bunch of shills paid by those companies.
  • Kyt - Sunday, December 3, 2017 - link

    There are better, yes. Some of us don't have access to all brands and models and when you are choosing between only 3 brands, you would want to know what you're getting and this is where this review becomes useful.

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