Load Regulation, Hold-Up Time, And 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.
Our hold-up time tests are described in detail here.
The hold-up time is low, though that's not the only problem. Lian Li's power-good signal lasts longer than the actual hold-up time. In other words, the PSU sends a power-good signal to the system even after its rails are out of spec.
Thankfully, the delay between power-good dropping and the moment the rails go out of spec is small at just 1.1 ms. Obviously, larger bulk caps are needed to lengthen the hold-up time.
For details on our inrush current testing, please click here.
The inrush current lands where we'd expect it.
Load Regulation And Efficiency Measurements
The first set of tests reveals the stability of the voltage rails and the PSU's efficiency. The applied load equals (approximately) 10 to 110 percent of the maximum load the supply can handle, 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 0.1 A. This test reveals whether a PSU is Haswell-ready 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||Fan Noise||Temps (In/Out)||PF/AC Volts|
|1||4.458A||1.965A||1.974A||0.981A||74.75||90.67%||0 RPM||0 dB(A)||42.48 °C||0.934|
|2||9.973A||2.939A||2.974A||1.180A||149.67||93.46%||0 RPM||0 dB(A)||44.12 °C||0.962|
|3||15.853A||3.446A||3.494A||1.383A||224.85||93.39%||820 RPM||26.1 dB(A)||41.50 °C||0.978|
|4||21.733A||3.943A||3.987A||1.585A||299.72||93.06%||1055 RPM||31.8 dB(A)||41.70 °C||0.982|
|5||27.277A||4.941A||5.002A||1.787A||374.69||92.51%||1055 RPM||31.8 dB(A)||41.98 °C||0.986|
|6||32.824A||5.934A||6.023A||1.989A||449.60||91.07%||1735 RPM||42.7 dB(A)||43.97 °C||0.988|
|7||38.385A||6.946A||7.053A||2.196A||524.57||90.07%||1910 RPM||45.3 dB(A)||44.33 °C||0.991|
|8||43.957A||7.950A||8.091A||2.404A||599.53||89.24%||2155 RPM||49.8 dB(A)||45.03 °C||0.993|
|9||49.984A||8.470A||8.641A||2.406A||674.62||88.46%||2205 RPM||50.0 dB(A)||45.19 °C||0.994|
|10||55.967A||8.979A||9.159A||2.512A||749.47||87.65%||2220 RPM||50.1 dB(A)||45.54 °C||0.995|
|11||62.348A||8.994A||9.180A||2.515A||824.36||86.88%||2220 RPM||50.1 dB(A)||46.07 °C||0.996|
|CL1||0.101A||10.011A||10.005A||0.000A||85.04||84.87%||1910 RPM||45.3 dB(A)||44.31 °C||0.945|
|CL2||61.937A||1.003A||1.003A||1.000A||746.69||88.26%||2220 RPM||50.1 dB(A)||45.56 °C||0.995|
The +12V rail's load regulation is pretty tight, while the 5V rail also fares well. The 3.3V rail isn't as strong; it registers greater-than 3 percent deviation.
We measure very high efficiency in the 20 percent and 50 percent load tests, though under full load it lands far from the 80 PLUS Platinum certification's 89 percent threshold. Then again, we push the PSUs we test hard with ambient temperatures in excess of 45 °C. The 80 PLUS organization uses much more forgiving conditions.
Despite high temperatures inside our box, the PE-750 operates passively up to the 20 percent load test. Even at 50 percent, the fan's noise is low. But after that it accelerates quickly, reaching 50 dB(A) during the 90 percent to 110 percent load tests. Apparently, the fan profile gets aggressive under harsh operating conditions. If Lian Li used an FDB fan instead, our noise readings might have been lower. And with such a large heat sink on the primary side, we think the fan profile could be relaxed a bit.