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Lian Li PE-750 SFX-L 750W PSU Review

Lian Li enters the PSU market again with two new SFX-L models featuring 550 W and 750 W capacities. The PE-750 is under the microscope today. It features modular cabling, a single +12V rail, and a semi-passive fan.

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.

Hold-Up Time

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.

Inrush Current

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 #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan SpeedFan NoiseTemps (In/Out)PF/AC Volts
14.458A1.965A1.974A0.981A74.7590.67%0 RPM0 dB(A)42.48 °C0.934
11.925V5.099V3.338V5.077V82.4440.51 °C115.1V
29.973A2.939A2.974A1.180A149.6793.46%0 RPM0 dB(A)44.12 °C0.962
11.916V5.091V3.326V5.066V160.1541.53 °C115.1V
315.853A3.446A3.494A1.383A224.8593.39%820 RPM26.1 dB(A)41.50 °C0.978
11.907V5.080V3.318V5.053V240.7645.88 °C115.1V
421.733A3.943A3.987A1.585A299.7293.06%1055 RPM31.8 dB(A)41.70 °C0.982
11.897V5.069V3.309V5.039V322.0846.40 °C115.1V
527.277A4.941A5.002A1.787A374.6992.51%1055 RPM31.8 dB(A)41.98 °C0.986
11.886V5.061V3.296V5.028V405.0146.99 °C115.1V
632.824A5.934A6.023A1.989A449.6091.07%1735 RPM42.7 dB(A)43.97 °C0.988
11.877V5.053V3.286V5.014V493.6749.58 °C115.1V
738.385A6.946A7.053A2.196A524.5790.07%1910 RPM45.3 dB(A)44.33 °C0.991
11.866V5.042V3.274V5.000V582.4350.33 °C115.1V
843.957A7.950A8.091A2.404A599.5389.24%2155 RPM49.8 dB(A)45.03 °C0.993
11.856V5.031V3.262V4.987V671.8251.48 °C115.1V
949.984A8.470A8.641A2.406A674.6288.46%2205 RPM50.0 dB(A)45.19 °C0.994
11.844V5.022V3.251V4.981V762.6751.96 °C115.1V
1055.967A8.979A9.159A2.512A749.4787.65%2220 RPM50.1 dB(A)45.54 °C0.995
11.833V5.015V3.243V4.970V855.0352.74 °C115.1V
1162.348A8.994A9.180A2.515A824.3686.88%2220 RPM50.1 dB(A)46.07 °C0.996
11.823V5.007V3.235V4.964V948.9053.62 °C115.1V
CL10.101A10.011A10.005A0.000A85.0484.87%1910 RPM45.3 dB(A)44.31 °C0.945
11.924V5.076V3.300V5.106V100.2049.82 °C115.1V
CL261.937A1.003A1.003A1.000A746.6988.26%2220 RPM50.1 dB(A)45.56 °C0.995
11.840V5.036V3.281V5.014V846.0152.71 °C115.1V

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.

Aris Mpitziopoulos
Contributing Editor

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