Corsair TX550M Power Supply Review

The TX550M is another good PSU by Corsair.

Corsair TX550M
(Image: © Tom's Hardware)

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Primary Rails And 5VSB Load Regulation

The following charts show the main rails' voltage values recorded between a range of 40W up to the PSU's maximum specified load, along with the deviation (in percent). Tight regulation is an important consideration every time we review a power supply because it facilitates constant voltage levels despite varying loads. Tight load regulation also, among other factors, improves the system’s stability, especially under overclocked conditions and, at the same time, it applies less stress to the DC-DC converters that many system components utilize.

Load regulation is tight on all rails! The fixed cables play role in this. 

Hold-Up Time

Put simply; hold-up time is the amount of time that the system can continue to run without shutting down or rebooting during a power interruption.

The hold-up time is close to 21ms, and the power ok signal is accurate and over 16ms, so everything is fine here. 

Inrush Current

Inrush current, or switch-on surge, refers to the maximum, instantaneous input current drawn by an electrical device when it is first turned on. A large enough inrush current can cause circuit breakers and fuses to trip. It can also damage switches, relays, and bridge rectifiers. As a result, the lower the inrush current of a PSU right as it is turned on, the better.

The inrush current is low with 115V, but higher than expected with 230V. 

Leakage Current

In layman's terms, leakage current is the unwanted transfer of energy from one circuit to another. In power supplies, it is the current flowing from the primary side to the ground or the chassis, which in the majority of cases is connected to the ground. For measuring leakage current, we use a GW Instek GPT-9904 electrical safety tester instrument.

The leakage current test is conducted at 110% of the DUT's rated voltage input (so for a 230-240V device, we should conduct the test with 253-264V input). The maximum acceptable limit of a leakage current is 3.5 mA and it is defined by the IEC-60950-1 regulation, ensuring that the current is low and will not harm any person coming in contact with the power supply's chassis.

Corsair TX550M

(Image credit: Tom's Hardware)

Leakage current is low. 

10-110% Load Tests

These tests reveal the PSU's load regulation and efficiency levels under high ambient temperatures. They also show how the fan speed profile behaves under increased operating temperatures.

Swipe to scroll horizontally
Test12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])Temps (In/Out)PF/AC Volts
10%2.783A2.008A2.008A0.992A54.99181.733%86421.440.01°C0.933
Row 2 - Cell 0 11.997V4.979V3.287V5.038V67.281Row 2 - Cell 6 Row 2 - Cell 7 Row 2 - Cell 8 45.39°C115.15V
20%6.589A3.013A3.013A1.192A109.91987.913%86821.640.64°C0.968
Row 4 - Cell 0 11.992V4.978V3.286V5.032V125.032Row 4 - Cell 6 Row 4 - Cell 7 Row 4 - Cell 8 46.36°C115.15V
30%10.749A3.517A3.516A1.392A164.90790.159%86721.541.09°C0.976
Row 6 - Cell 0 11.988V4.977V3.285V5.027V182.907Row 6 - Cell 6 Row 6 - Cell 7 Row 6 - Cell 8 47.38°C115.14V
40%14.939A4.02A4.02A1.593A219.9890.829%87021.641.93°C0.983
Row 8 - Cell 0 11.967V4.976V3.283V5.022V242.191Row 8 - Cell 6 Row 8 - Cell 7 Row 8 - Cell 8 48.48°C115.14V
50%18.766A5.027A5.028A1.794A274.96690.815%93324.042.23°C0.987
Row 10 - Cell 0 11.961V4.974V3.282V5.017V302.777Row 10 - Cell 6 Row 10 - Cell 7 Row 10 - Cell 8 49.44°C115.14V
60%22.594A6.034A6.036A1.995A329.95290.54%96325.242.84°C0.989
Row 12 - Cell 0 11.956V4.973V3.28V5.011V364.428Row 12 - Cell 6 Row 12 - Cell 7 Row 12 - Cell 8 50.67°C115.14V
70%26.435A7.041A7.046A2.196A384.91590.169%97425.743.01°C0.991
Row 14 - Cell 0 11.947V4.971V3.278V5.006V426.884Row 14 - Cell 6 Row 14 - Cell 7 Row 14 - Cell 8 51.38°C115.15V
80%30.261A8.002A8.053A2.298A439.10589.48%116931.243.81°C0.992
Row 16 - Cell 0 11.945V4.97V3.277V5.001V490.731Row 16 - Cell 6 Row 16 - Cell 7 Row 16 - Cell 8 52.71°C115.14V
90%34.495A8.552A8.545A2.401A494.34488.833%126632.944.35°C0.993
Row 18 - Cell 0 11.940V4.969V3.276V4.996V556.49Row 18 - Cell 6 Row 18 - Cell 7 Row 18 - Cell 8 53.85°C115.13V
100%38.526A9.058A9.067A3.005A549.55187.99%140236.245.93°C0.993
Row 20 - Cell 0 11.937V4.967V3.274V4.99V624.563Row 20 - Cell 6 Row 20 - Cell 7 Row 20 - Cell 8 56.24°C115.12V
110%42.431A10.067A10.172A3.008A604.57187.065%151537.846.82°C0.993
Row 22 - Cell 0 11.932V4.966V3.273V4.985V694.392Row 22 - Cell 6 Row 22 - Cell 7 Row 22 - Cell 8 57.69°C115.12V
CL10.115A14.508A14.537A0A121.27183.257%111529.642.37°C0.971
Row 24 - Cell 0 11.991V4.977V3.281V5.021V145.659Row 24 - Cell 6 Row 24 - Cell 7 Row 24 - Cell 8 49.27°C115.14V
CL20.114A20.074A0A0A101.37782.481%100727.043.17°C0.967
Row 26 - Cell 0 11.996V4.982V3.282V5.03V122.91Row 26 - Cell 6 Row 26 - Cell 7 Row 26 - Cell 8 50.73°C115.14V
CL30.114A0A25.103A0A83.86776.627%98726.344.77°C0.964
Row 28 - Cell 0 11.991V4.975V3.286V5.024V109.45Row 28 - Cell 6 Row 28 - Cell 7 Row 28 - Cell 8 53.57°C115.14V
CL445.993A0A0A0A549.38689.347%135235.045.78°C0.993
Row 30 - Cell 0 11.945V4.972V3.281V5.007V614.896Row 30 - Cell 6 Row 30 - Cell 7 Row 30 - Cell 8 55.93°C115.12V

The PSU copes nicely with high operating temperatures, without needing high airflow which translates to increase noise output. 

20-80W Load Tests

In the following tests, we measure the PSU's efficiency at loads significantly lower than 10% of its maximum capacity (the lowest load the 80 PLUS standard measures). This is important for representing when a PC is idle with power-saving features turned on.

Swipe to scroll horizontally
Test12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])Temps (In/Out)PF/AC Volts
20W1.238A0.502A0.502A0.198A19.99377.106%85921.236.78°C0.842
Row 2 - Cell 0 11.989V4.981V3.289V5.044V25.93Row 2 - Cell 6 Row 2 - Cell 7 Row 2 - Cell 8 39.84°C115.15V
40W2.724A0.703A0.703A0.297A39.99178.968%85821.136.88°C0.915
Row 4 - Cell 0 11.998V4.98V3.288V5.042V50.642Row 4 - Cell 6 Row 4 - Cell 7 Row 4 - Cell 8 40.74°C115.16V
60W4.211A0.904A0.903A0.397A59.99183.393%86221.338.67°C0.937
Row 6 - Cell 0 11.997V4.98V3.288V5.04V71.937Row 6 - Cell 6 Row 6 - Cell 7 Row 6 - Cell 8 42.85°C115.15V
80W5.694A1.105A1.104A0.496A79.9386.052%86321.339.31°C0.954
Row 8 - Cell 0 11.996V4.979V3.287V5.038V92.886Row 8 - Cell 6 Row 8 - Cell 7 Row 8 - Cell 8 43.85°C115.15V

With light loads the fan spins at low speeds, so noise output remains low. 

2% or 10W Load Test

From July 2020, the ATX spec requires 70% and higher efficiency with 115V input. The applied load is only 10W for PSUs with 500W and lower capacities, while for stronger units, we dial 2% of their max-rated capacity.

Swipe to scroll horizontally
12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])Temps (In/Out)PF/AC Volts
0.727A0.222A0.278A0.051A10.98767.802%82319.825.61°C0.752
Row 2 - Cell 0 11.986V4.978V3.286V5.046V16.205Row 2 - Cell 6 Row 2 - Cell 7 26.4°C115.14V

The PSU breaks the 60% barrier, it would be nice to see over 70% efficiency though, in this test. 

Efficiency & Power Factor

Next, we plotted a chart showing the PSU's efficiency at low loads and loads from 10 to 110% of its maximum rated capacity. The higher a PSU’s efficiency, the less energy goes wasted, leading to a reduced carbon footprint and lower electricity bills. The same goes for Power Factor.

At high loads, efficiency takes a big hit with 115V input. Nonetheless, still the platforms is efficient with a lower voltage input under all load conditions. We would like to see a little higher PF readings with 230V input, where most APFC converters don't performs so well. 

5VSB Efficiency

Swipe to scroll horizontally
Test #5VSBDC/AC (Watts)EfficiencyPF/AC Volts
10.1A0.505W77.815%0.093
Row 2 - Cell 0 5.046V0.649WRow 2 - Cell 3 115.19V
20.25A1.261W81.308%0.189
Row 4 - Cell 0 5.045V1.551WRow 4 - Cell 3 115.19V
30.55A2.774W82.472%0.293
Row 6 - Cell 0 5.045V3.364WRow 6 - Cell 3 115.18V
41A5.043W82.758%0.359
Row 8 - Cell 0 5.044V6.094WRow 8 - Cell 3 115.17V
51.5A7.564W82.018%0.396
Row 10 - Cell 0 5.043V9.222WRow 10 - Cell 3 115.16V
62.999A15.113W79.486%0.449
Row 12 - Cell 0 5.039V19.014WRow 12 - Cell 3 115.15V

The 5VSB rail is highly efficient! 

Power Consumption In Idle And Standby

Swipe to scroll horizontally
Mode12V5V3.3V5VSBWattsPF/AC Volts
Idle11.968V4.975V3.284V5.047V4.1740.392
Row 2 - Cell 0 Row 2 - Cell 1 Row 2 - Cell 2 Row 2 - Cell 3 Row 2 - Cell 4 Row 2 - Cell 5 115.14V
StandbyRow 3 - Cell 1 Row 3 - Cell 2 Row 3 - Cell 3 Row 3 - Cell 4 0.0480.007
Row 4 - Cell 0 Row 4 - Cell 1 Row 4 - Cell 2 Row 4 - Cell 3 Row 4 - Cell 4 Row 4 - Cell 5 115.14V

Vampire power is low with both voltage inputs. 

Fan RPM, Delta Temperature, And Output Noise

All results are obtained between an ambient temperature of 37 to 47 degrees Celsius (98.6 to 116.6 degrees Fahrenheit).

(Image credit: Tom's Hardware)

(Image credit: Tom's Hardware)

The fan speed profile is not aggressive, even at high operating temperatures. 

The following results were obtained at 30 to 32 degrees Celsius (86 to 89.6 degrees Fahrenheit) ambient temperature.       

(Image credit: Tom's Hardware)

(Image credit: Tom's Hardware)

At average operating temperatures close to 30 degrees Celsius, the PSU is silent with up to 355W loads at 12V. with 440W on the same rail the PSU passes the 30 dBA mark.

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Aris Mpitziopoulos
Contributing Editor

Aris Mpitziopoulos is a contributing editor at Tom's Hardware, covering PSUs.