Bitfenix Formula Gold 650W PSU Review

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 measure is longer than 17ms, while the power-good signal is accurate and only a hair away from 16ms.

Inrush Current

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

The inrush current with 115V is low. However, this is not the case with 230V input.

Load Regulation And Efficiency Measurements

The first set of tests reveals the stability of the voltage rails and the BF650G'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.

Swipe to scroll horizontally
Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan SpeedPSU NoiseTemps (In/Out)PF/AC Volts
13.580A1.983A1.967A0.987A64.82885.807%480 RPM9.6 dB(A)37.87°C0.958
28.159A2.976A2.953A1.187A129.33589.922%480 RPM9.6 dB(A)38.42°C0.980
313.146A3.474A3.429A1.387A194.43591.082%480 RPM9.6 dB(A)38.74°C0.986
418.144A3.971A3.940A1.589A259.66291.237%480 RPM9.6 dB(A)39.55°C0.988
522.815A4.966A4.926A1.791A324.94991.031%480 RPM9.6 dB(A)40.17°C0.990
627.433A5.958A5.913A1.995A389.48889.844%695 RPM15.4 dB(A)41.57°C0.989
732.129A6.957A6.904A2.200A454.79689.252%907 RPM23.3 dB(A)42.19°C0.989
836.836A7.953A7.893A2.405A520.11588.585%1153 RPM30.8 dB(A)43.09°C0.990
941.953A8.453A8.375A2.408A585.03387.932%1515 RPM37.0 dB(A)44.00°C0.991
1047.016A8.953A8.886A2.512A649.76187.164%1844 RPM41.9 dB(A)45.16°C0.992
1152.490A8.956A8.891A2.515A714.59186.272%2043 RPM44.7 dB(A)46.11°C0.993
CL10.738A12.002A12.000A0.000A109.51585.599%505 RPM8.9 dB(A)43.37°C0.977
CL254.179A1.000A1.001A1.000A661.54787.667%1902 RPM43.5 dB(A)45.29°C0.992

Load regulation on the +12V rail falls within 1%. But we expected an even better result, given the native cables. Our results are better on the minor rails, with both 5V and 3.3V staying within 0.4%.

Efficiency-wise, the BF650G does satisfy the 80 PLUS Gold standard's requirements, despite the tough operating conditions we apply.

Noise is minimal up to about 50% load, it remains below 30 dB(A) with up to 70% load, and only goes over 40 dB(A) during our full-load test. In general, this is a quiet PSU, even though it doesn't have a semi-passive fan mode.

The power factor readings are a little on the low side, though they don't give us cause for worry.

MORE: Best Power Supplies

MORE: How We Test Power Supplies

MORE: All Power Supply Content

Contributing Editor

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

  • Dark Lord of Tech
    Great Review..Thanks!
  • turkey3_scratch
    Man this one is great! Thanks for the review, I appreciate the hard work you put into them.
  • Lutfij
    Was a great read for the weekend and an interesting one too. Keep up the good work Aris! ;)