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.
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.
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 hold-up time we measured was longer than 17ms. However, the power-good signal's duration didn't reach the 16ms mandated by the ATX specification. At least it's accurate.
Inrush Current
For details on our inrush current testing, please click here.
With 115V input, the inrush current is low. It's much higher with 230V input, though.
Load Regulation And Efficiency Measurements
The first set of tests reveals the stability of the voltage rails and the SF600’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 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 | PSU Noise | Temps (In/Out) | PF/AC Volts |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 3.160A | 1.970A | 1.953A | 0.993A | 60.123 | 85.790% | 0 RPM | <6.0 dB(A) | 47.48°C | 0.976 |
| 12.191V | 5.077V | 3.379V | 5.034V | 70.082 | 39.28°C | 115.29V | ||||
| 2 | 7.295A | 2.955A | 2.931A | 1.193A | 119.829 | 90.149% | 0 RPM | <6.0 dB(A) | 49.22°C | 0.969 |
| 12.190V | 5.077V | 3.378V | 5.029V | 132.924 | 40.27°C | 115.22V | ||||
| 3 | 11.791A | 3.448A | 3.406A | 1.393A | 179.731 | 91.489% | 0 RPM | <6.0 dB(A) | 50.81°C | 0.976 |
| 12.189V | 5.077V | 3.378V | 5.025V | 196.451 | 41.22°C | 115.14V | ||||
| 4 | 16.292A | 3.943A | 3.912A | 1.594A | 239.754 | 91.860% | 1319 RPM | 14.0 dB(A) | 41.80°C | 0.983 |
| 12.186V | 5.075V | 3.376V | 5.020V | 260.998 | 51.80°C | 115.16V | ||||
| 5 | 20.463A | 4.928A | 4.889A | 1.795A | 299.853 | 91.835% | 1334 RPM | 14.3 dB(A) | 42.03°C | 0.987 |
| 12.185V | 5.075V | 3.375V | 5.015V | 326.514 | 52.93°C | 115.07V | ||||
| 6 | 24.632A | 5.914A | 5.868A | 1.996A | 359.948 | 91.516% | 1544 RPM | 18.9 dB(A) | 42.80°C | 0.990 |
| 12.185V | 5.074V | 3.374V | 5.010V | 393.319 | 54.23°C | 115.00V | ||||
| 7 | 28.762A | 6.900A | 6.847A | 2.198A | 419.635 | 90.720% | 1812 RPM | 23.0 dB(A) | 43.23°C | 0.992 |
| 12.187V | 5.074V | 3.374V | 5.005V | 462.562 | 55.16°C | 114.90V | ||||
| 8 | 32.969A | 7.886A | 7.826A | 2.400A | 480.138 | 90.230% | 2410 RPM | 32.1 dB(A) | 43.71°C | 0.993 |
| 12.185V | 5.074V | 3.373V | 5.000V | 532.128 | 56.12°C | 114.91V | ||||
| 9 | 37.504A | 8.380A | 8.304A | 2.401A | 539.423 | 89.731% | 2931 RPM | 37.1 dB(A) | 44.51°C | 0.994 |
| 12.183V | 5.073V | 3.372V | 4.998V | 601.156 | 57.46°C | 114.82V | ||||
| 10 | 42.136A | 8.876A | 8.814A | 2.504A | 600.275 | 89.180% | 3021 RPM | 37.6 dB(A) | 45.23°C | 0.995 |
| 12.176V | 5.072V | 3.370V | 4.994V | 673.104 | 58.69°C | 114.73V | ||||
| 11 | 47.056A | 8.878A | 8.818A | 2.505A | 660.338 | 88.459% | 3839 RPM | 44.3 dB(A) | 46.16°C | 0.996 |
| 12.179V | 5.072V | 3.369V | 4.992V | 746.489 | 60.34°C | 114.73V | ||||
| CL1 | 0.151A | 14.006A | 14.000A | 0.000A | 120.341 | 86.334% | 904 RPM | 7.1 dB(A) | 43.40°C | 0.970 |
| 12.201V | 5.081V | 3.381V | 5.037V | 139.390 | 55.07°C | 115.30V | ||||
| CL2 | 50.024A | 1.003A | 1.000A | 1.000A | 622.662 | 89.514% | 3459 RPM | 41.2 dB(A) | 45.72°C | 0.995 |
| 12.178V | 5.072V | 3.369V | 5.014V | 695.602 | 59.51°C | 114.80V |
These load regulation numbers are super-tight, setting an example for all of the other high-end SFX-based PSUs to follow. When it comes to efficiency, the 80 PLUS Platinum standard's requirements are satisfied under 20% and full loads. It comes close to 92% at a 50% load. Keep in mind that we test at much higher ambient temperatures than the 80 PLUS organization, so lower efficiency readings are expected.
The cooling fan's profile is very relaxed. It only gets crazy with 110% load and in an ambient environment warmer than 46°C. Moreover, the semi-passive mode lasts up to our third test, since load on the minor rails remains low. As the load increases on those rails, the fan kicks in to cool the DC-DC converters responsible for generating those rails.
MORE: Best Power Supplies
MORE: How We Test Power Supplies
MORE: All Power Supply Content
