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Gigabyte UD750GM Power Supply Review

Decent, efficient, and with a reasonable price tag.

Gigabyte UD750GM
(Image: © Tom's Hardware)

To learn more about our PSU tests and methodology, please check out How We Test Power Supply Units. 

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 at 12V, tight enough at 5V, and loose at 3.3V. 

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 meets the ATX spec's requirement of 17 ms and the power ok signal is accurate and longer than 16 ms. 

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 pretty high 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.

Gigabyte UD750GM

(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.

Test12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])Temps (In/Out)PF/AC Volts
10%4.416A1.951A1.954A0.987A75.00386.284%0<6.045.13°C0.954
12.094V5.126V3.378V5.064V86.9340.54°C115.1V
20%9.845A2.93A2.939A1.187A149.94889.733%0<6.046.07°C0.972
12.092V5.119V3.368V5.054V167.10240.7°C115.08V
30%15.629A3.421A3.434A1.387A224.95391.127%94327.941.26°C0.98
12.087V5.116V3.364V5.047V246.85347.08°C115.06V
40%21.430A3.915A3.935A1.588A300.05691.602%95028.241.54°C0.984
12.079V5.109V3.354V5.038V327.55947.64°C115.04V
50%26.851A4.899A4.933A1.79A374.61291.384%95828.342.17°C0.985
12.071V5.103V3.345V5.028V409.93748.69°C115.02V
60%32.307A5.887A5.937A1.993A449.56390.95%125034.442.85°C0.987
12.064V5.097V3.335V5.018V494.29949.94°C115V
70%37.769A6.877A6.944A2.197A524.4790.32%170141.143.62°C0.987
12.056V5.09V3.327V5.009V580.6851.13°C114.98V
80%43.303A7.871A7.954A2.3A599.66389.743%195544.543.73°C0.988
12.049V5.084V3.319V5.001V668.19652.06°C114.96V
90%49.173A8.372A8.454A2.403A674.62189.225%198544.844.76°C0.989
12.042V5.077V3.312V4.995V756.08254.04°C114.93V
100%54.852A8.876A8.994A3.014A749.81888.446%197244.645.43°C0.986
12.034V5.07V3.302V4.977V847.77355.52°C114.91V
110%60.401A9.883A10.095A3.017A824.76987.771%198644.846.66°C0.986
12.028V5.059V3.298V4.972V939.66957.51°C114.89V
CL10.115A12.337A12.417A0A106.28683.897%0<6.048.72°C0.967
12.090V5.123V3.357V5.073V126.68342.25°C115.09V
CL20.115A19.539A0A0A101.39982.618%0<6.050.53°C0.966
12.092V5.119V3.366V5.078V122.73643.17°C115.09V
CL30.115A0A19.702A0A67.37777.141%0<6.052.61°C0.955
12.090V5.114V3.349V5.075V87.3444.52°C115.1V
CL462.269A0A0A0A749.5589.433%199444.845.74°C0.99
12.037V5.062V3.324V5.048V838.10355.85°C114.91V

We pushed hard this PSU during these tests, but it didn't budge. 

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.

Test12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])Temps (In/Out)PF/AC Volts
20W1.228A0.488A0.487A0.197A20.00169.932%0<6.040.09°C0.876
12.097V5.123V3.385V5.085V28.60637.04°C115.12V
40W2.704A0.683A0.683A0.295A40.00281.058%0<6.040.71°C0.926
12.086V5.121V3.383V5.082V49.34937.45°C115.11V
60W4.180A0.879A0.878A0.394A60.00185.662%0<6.042.23°C0.946
12.090V5.12V3.382V5.078V70.04238.48°C115.11V
80W5.650A1.074A1.074A0.493A79.95287.795%0<6.044.03°C0.956
12.093V5.122V3.38V5.075V91.06339.98°C115.1V

Despite the high operating temperatures, the PSU's fan didn't engage in these tests because of the low thermal loads. 

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.

12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])Temps (In/Out)PF/AC Volts
1.072A0.223A0.223A0.053A15.1266.991%0<6.026.7°C0.86
12.087V5.121V3.387V5.09V22.57923.74°C115.11V

With only 2% of its max-rated capacity, the platform delivers over 60% efficiency. 

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.

Efficiency is high with normal loads, but it drops with lighter loads. 

5VSB Efficiency

Test #5VSBDC/AC (Watts)EfficiencyPF/AC Volts
10.1A0.509W74.356%0.092
5.09V0.685W115.12V
20.25A1.272W78.671%0.193
5.087V1.617W115.12V
30.55A2.795W80.059%0.318
5.081V3.491W115.12V
41A5.072W80.616%0.404
5.072V6.291W115.12V
51.5A7.593W80.853%0.442
5.061V9.391W115.12V
63A15.092W78.882%0.496
5.03V19.132W115.12V

The 5VSB rail is efficient. 

Power Consumption In Idle And Standby

Mode12V5V3.3V5VSBWattsPF/AC Volts
Idle12.092V5.122V3.393V5.092V7.9630.624
115.12V
Standby0.0340.007
115.12V

Vampire power should be lower with 230V input. 

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 gets aggressive with high loads and increased operating temperatures, to protect the mediocre quality filtering caps on the secondary side, 

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 normal operating temperatures, close to 30 degrees Celsius, the PSU's passive operation doesn't last long, especially if you apply high loads on the minor rails. For the most part, the cooling fan's noise is in the 25-30 dBA range, which is acceptable, and with 550W and higher loads, it exceeds 30 dBA. With 580W, the noise goes over 35 dBA, and with anything above 650W, the PSU's noise exceeds 40 dBA. 

MORE: Best Power Supplies

MORE: How We Test Power Supplies

MORE: All Power Supply Content

Aris Mpitziopoulos
Aris Mpitziopoulos

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.

  • Tom Sunday
    I will shortly be in the market for a new PSU and as part of a complete new generation ‘PC Build’ this coming December. Due to the extreme system importance of a PSU selection I never at first look at the pricing or its reasonable cost compared to other brands. But surely a 10-year unblemished warranty has usually driven me to EVGA and SEASONIC products. I am also now prone in looking at PSU’s with over 1200W as the new 4000 series GPU’s and other hardware coming on stream will become so much more demanding and power hungry. Enthusiasts I believe will also now be keeping their primary “Builds” much longer (5-years or more?) as hardware cost are spiraling out of control. So 10-year warranties and RMA services area big deal for me among many other expected PSU offerings like direct software control, digital readouts on the PSU itself, high quality cabling and product finishes.
    Reply
  • PiranhaTech
    I'm curious if you did the GamersNexus tests. A lot of PC builders are going to wait for their tests before considering a Gigabyte PSU due to the exploding PSU issue they had

    aACtT_rzToIView: https://www.youtube.com/watch?v=aACtT_rzToI
    Reply