Home / Tech News / Featured Tech Reviews / be quiet! System Power U9 700W PSU Review

be quiet! System Power U9 700W PSU Review

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

Primary Rails And 5VSB Load Regulation

Load Regulation testing is detailed here.

Hold-Up Time

Our hold-up time tests are described in detail here.

The oscilloscope screenshots that we took during the hold-up time measurements:

The hold-up time is much lower than 17ms. This was expected since the bulk cap is small. At least the power ok signal is accurate.

Inrush Current

For details on our inrush current testing, please click here.

The inrush current is high, with both voltage inputs.

Load Regulation And Efficiency Measurements

The first set of tests reveals the stability of the voltage rails and the SU9-700’s efficiency. The applied load equals (approximately) 10 to 110 percent of the power supplies maximum load in increments of 10 percentage points.

We conducted two additional tests.

During the first, we stressed the two minor rails (5V and 3.3V) with a high load, while the load at +12V was only 0.1A. This test reveals whether a power supply is compatible with Intel’s C6/C7 sleep states or not. In the second test, we determined the maximum load the +12V rail could handle with minimal load on the minor rails.

Test # 12V 5V 3.3V 5VSB DC/AC (Watts) Efficiency Fan Speed (RPM) PSU Noise (dB[A]) Temps (In/Out) PF/AC Volts
1 3.950A 1.995A 1.992A 0.988A 69.671 82.690% 633 10.0 36.53°C 0.963
12.170V 5.014V 3.311V 5.063V 84.256 39.66°C 115.26V
2 8.955A 2.994A 2.992A 1.188A 139.782 87.420% 630 10.0 36.82°C 0.970
12.158V 5.012V 3.308V 5.053V 159.897 40.68°C 115.18V
3 14.303A 3.492A 3.479A 1.388A 209.703 88.568% 628 9.9 37.23°C 0.979
12.145V 5.010V 3.305V 5.043V 236.770 41.96°C 115.18V
4 19.658A 3.998A 3.999A 1.590A 279.738 88.671% 635 10.1 37.46°C 0.984
12.133V 5.007V 3.303V 5.032V 315.478 42.75°C 115.07V
5 24.697A 4.999A 4.999A 1.793A 349.866 88.248% 628 9.9 37.87°C 0.988
12.121V 5.004V 3.300V 5.021V 396.458 44.07°C 114.97V
6 29.742A 6.001A 6.008A 1.997A 419.977 87.487% 630 10.0 38.09°C 0.990
12.109V 5.002V 3.297V 5.010V 480.045 45.86°C 114.97V
7 34.794A 7.005A 7.012A 2.202A 490.129 86.354% 656 10.7 38.70°C 0.992
12.100V 4.998V 3.295V 4.998V 567.579 47.30°C 114.84V
8 39.863A 8.009A 8.020A 2.407A 560.201 85.146% 948 20.0 39.27°C 0.993
12.086V 4.996V 3.292V 4.986V 657.928 48.49°C 114.73V
9 45.371A 8.505A 8.505A 2.409A 629.666 84.062% 988 21.1 39.93°C 0.994
12.060V 4.997V 3.291V 4.982V 749.046 49.86°C 114.65V
10 50.603A 9.013A 9.032A 3.024A 699.733 82.687% 1530 34.8 40.53°C 0.995
12.055V 4.994V 3.288V 4.962V 846.238 50.79°C 114.60V
11 56.481A 9.013A 9.038A 3.028A 769.783 81.321% 1812 39.2 40.90°C 0.995
12.041V 4.992V 3.286V 4.955V 946.599 51.94°C 114.46V
CL1 0.134A 16.002A 16.000A 0.000A 134.392 79.577% 644 10.4 37.76°C 0.973
12.165V 4.997V 3.300V 5.056V 168.884 44.31°C 115.15V
CL2 55.997A 1.000A 0.999A 1.000A 688.785 83.455% 1445 32.8 40.48°C 0.994
12.063V 4.996V 3.291V 5.009V 825.340 50.52°C 114.63V

For a budget-oriented product, the load regulation performance is amazing! The +12V, 5V and 3.3V rails stay within 1% and the platform doesn't have a problem delivering more than its nominal capacity at over 40°C ambient. Moreover, we have to push it really hard in order to make the fan spin at high speeds and still only in the overload scenario the acoustics noise reached close to 40 dB(A).

The performance with highly unbalanced loads among the rails is very good, since DC-DC converters are used for the generation of the minor rails. Moreover, the PF readings look good as well.

The 80 PLUS Bronze requirements are easily met in all three load scenarios (20%, 50% and 100%), even at high operating temperatures.

Become a Patron!

Check Also

NZXT H7 Flow (2024) Case Review

Don't be fooled, it's not the same case that came out in 2022 - but what's changed?