PowerSpec PSX 850GFM PSU Review: Micro Center's House Brand Scores A Hit

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Protection Features & DC Power Sequencing

Protection Features

Check out our PSUs 101 article to learn more about PSU protection features. Our protection features evaluation methodology is described in detail here.

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Protection Features
OCP12V: 95.2A (134.27%), 11.897V 5V: 34.8A (158.18%), 5.008V 3.3V: 33.9A (154.09%), 3.16V 5VSB: 4.5A (150%), 4.895V, 55mV ripple
OPP1092.85W (128.57%)
OTP✗ (>200°C @ 12V heat sink)
SCP12V: ✓ 5V: ✓ 3.3V: ✓ 5VSB: ✓ -12V: ✓
PWR_OKOperates properly
SIPSurge: MOV Inrush: -

Over-current protection on the 3.3V rail was set too high on the first two samples we received, leading to their failure. High Power examined our findings, identified the problem, and lowered the OCP trigger point on subsequent production batches. While the problem still exists in PSX 850GFMs already on the market, it's highly unlikely that you'll ever draw so much current from the 3.3V rail.

More troubling is that this platform either doesn't employ over-temperature protection, or it's set too high. We heated the 12V sinks up to 200°C and the PSU didn't shut down. The lack of an NTC thermistor is also a great shame, especially in a modern platform.

DC Power Sequencing

According to Intel’s most recent Power Supply Design Guide (revision 1.4), the 12V and 5V voltages must be equal or greater than the 3.3V rail’s output at all times, including power-up and normal operation.

For our first measurement, we turn the PSU off and switch it back on without any load. In the second test, we set the PSU to standby mode, dial full load, and then start the PSU. In the last test, while the PSU is completely switched off (we cut off the power or switch the PSU off), we dial full load before restoring power.

Everything looks fine, according to our results. The 12V and 5V voltages were clearly higher than 3.3V in every case.

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Aris Mpitziopoulos
Contributing Editor

Aris Mpitziopoulos is a contributing editor at Tom's Hardware, covering PSUs.

  • AnimeMania
    In the video, you should have turned on the PSU and shown all the RGB lighting choices.
  • JQB45
    So what low Tier-2, High Tier-3?
  • pureblackfire2
    I wouldn't consider this even if it's cheap. for non enthusiasts it's far from idiot proof enough to recommend. for power users they'd obviously want something better. meh.
  • Rexper
    Low quality sleeve bearing fan without Over Temperature Protection or Fan Failure Protection? No thanks.