Why you can trust Tom's Hardware Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you. Find out more about how we test.

Page 4 of 11:

Load Regulation, Hold-Up Time & Inrush Current

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

Thermaltake SPR-0850F-R

Riotoro Enigma 850W

EVGA 850 BQ

Primary Rails And 5VSB Load Regulation

Load Regulation testing is detailed here.

Image 1 of 8

Hold-Up Time

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

Image 1 of 7

The hold-up time we observed is higher than 17ms. However, the power-good signal doesn't exceed 16ms. At least it's accurate.

Inrush Current

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

Image 1 of 2

We measured almost the same inrush current with both 230V and 115V input. Readings above 60A are quite high; we'd like to see inrush currents lower than 50A.

Load Regulation And Efficiency Measurements

The first set of tests reveals the stability of the voltage rails and the SPR-0850F-R's efficiency. The applied load equals (approximately) 10 to 110 percent of the PSU's 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 PSU supports Intel's C6/C7 power states or not. In the second test, we determined the maximum load the +12V rail could handle with minimal load on the minor rails.

Swipe to scroll horizontally

Test #	12V	5V	3.3V	5VSB	DC/AC (Watts)	Efficiency	Fan Speed	Fan Noise	Temps (In/Out)	PF/AC Volts
1	5.158A	1.975A	1.978A	0.981A	84.802	81.804%	1420 RPM	36.0 dB(A)	38.56°C	0.960
12.256V	5.070V	3.329V	5.085V	103.665	42.45°C	115.11V
2	11.351A	2.959A	2.985A	1.184A	169.658	86.219%	1475 RPM	37.5 dB(A)	39.03°C	0.983
12.228V	5.060V	3.314V	5.062V	196.776	45.08°C	115.10V
3	17.928A	3.467A	3.514A	1.385A	254.888	87.372%	1600 RPM	38.7 dB(A)	39.81°C	0.983
12.205V	5.049V	3.299V	5.039V	291.727	44.98°C	115.09V
4	24.505A	3.972A	4.014A	1.593A	339.776	87.476%	1660 RPM	40.3 dB(A)	40.69°C	0.986
12.185V	5.037V	3.285V	5.015V	388.420	47.14°C	115.09V
5	30.775A	4.973A	5.045A	1.801A	424.671	87.124%	1680 RPM	40.9 dB(A)	41.18°C	0.988
12.159V	5.026V	3.270V	4.990V	487.433	48.87°C	115.08V
6	37.075A	5.983A	6.085A	2.011A	509.653	86.493%	1760 RPM	42.8 dB(A)	42.08°C	0.989
12.134V	5.015V	3.253V	4.965V	589.240	51.30°C	115.08V
7	43.390A	7.001A	7.138A	2.225A	594.616	85.639%	1795 RPM	43.6 dB(A)	42.89°C	0.990
12.111V	5.004V	3.236V	4.938V	694.327	53.91°C	115.07V
8	49.746A	8.018A	8.201A	2.441A	679.518	84.639%	1815 RPM	43.7 dB(A)	43.67°C	0.991
12.084V	4.990V	3.218V	4.910V	802.840	48.06°C	115.07V
9	56.554A	8.539A	8.767A	2.446A	764.573	83.728%	1825 RPM	43.8 dB(A)	44.63°C	0.992
12.059V	4.978V	3.205V	4.899V	913.167	57.46°C	115.07V
10	63.129A	9.067A	9.313A	3.093A	849.331	82.421%	1825 RPM	43.8 dB(A)	45.08°C	0.992
12.033V	4.965V	3.189V	4.844V	1030.480	56.38°C	115.06V
11	70.325A	9.088A	9.355A	3.103A	934.359	81.131%	1825 RPM	43.8 dB(A)	46.45°C	0.992
12.011V	4.951V	3.175V	4.830V	1151.665	55.29°C	115.05V
CL1	0.100A	17.022A	17.003A	0.005A	143.268	79.120%	1740 RPM	42.0 dB(A)	44.76°C	0.986
12.204V	5.087V	3.260V	5.106V	181.077	44.96°C	115.11V
CL2	70.793A	1.003A	1.003A	1.002A	865.765	82.652%	1825 RPM	43.8 dB(A)	46.28°C	0.993
12.043V	4.954V	3.224V	4.993V	1047.486	51.08°C	115.06V

Load regulation on the +12V and 5V rails is within 3%. It's quite loose at 3.3V, though. Moreover, during tests #10 and #11, this rail drops its voltage below 3.2V. While the 3.3V rail is only lightly used, it still needs to stay as close as possible to the nominal voltage. Load regulation at 5VSB is quite bad, landing to close to 6%.

The SPR-0850F-R operates trouble-free under very high ambient temperatures. However, during the full-load and overload tests, its efficiency takes a huge hit. What's more, the fan profile is too aggressive under increased operating temperatures, so don't expect this PSU to be quiet once you stress it. Given the low efficiency rating, we completely understand why Thermaltake preferred an aggressive fan profile. The long warranty also plays a role, since this PSU has to last at least seven years. That won't be easy if it's subjected to high loads most of the time.

MORE: Best Power Supplies
MORE: How We Test Power Supplies
MORE: All Power Supply Content