Protection Features, DC Power Sequencing, Cross-Load Tests and Infrared Images
Check out our PSUs 101 article to learn more about PSU protection features.
|OCP||12V: 74.2A (134.91%), 11.875V 5V: 29.2A (146%), 5.003V 3.3V: 30.6A (153%), 3.259V 5VSB: 5.1A (170%), 4.875V|
|OTP||✓ (142°C @ 12V heat sink)|
|SCP||12V: ✓ 5V: ✓ 3.3V: ✓ 5VSB: ✓ -12V: ✓|
|PWR_OK||Accurate but lower than 16ms|
|SIP||Surge: MOV Inrush: NTC Thermistor & Bypass Relay|
The OCP triggering points on the minor rails should be lower, close to 130%. There is no point for so high amperage on those rails, which are only lightly used nowadays. Moreover, there are no proper heat sinks on the DC-DC converters that generate the 5V and 3.3V rails, so such high loads can create problems.
The power ok signal is accurate, but lower than 16ms which is what the ATX spec requires. This can be easily fixed though, since the hold-up time is quite long at almost 20ms.
DC Power Sequencing
According to Intel’s most recent Power Supply Design Guide (revision 1.4), the +12V and 5V outputs must be equal to or greater than the 3.3V rail at all times. Unfortunately, Intel doesn't mention why it is so important to always keep the 3.3V rail's voltage lower than the levels of the other two outputs.
No problems here since the 3.3V rail's voltage is lower in all tests.
Cross Load Tests
To generate the following charts, we set our loaders to auto mode through custom-made software before trying more than 25,000 possible load combinations with the +12V, 5V, and 3.3V rails. The deviations in each of the charts below are calculated by taking the nominal values of the rails (12V, 5V, and 3.3V) as point zero. The ambient temperature during testing was between 30 to 32 degrees Celsius (86 to 89.6 degrees Fahrenheit).
Load Regulation Charts
The highest efficiency region is with 160W to 360W load at +12V, with the combined load on the minor rails staying below 35W.
The lower the power supply's ripple, the more stable the system will be and less stress will also be applied to its components.
We apply a half-load for 10 minutes with the PSU's top cover and cooling fan removed before taking photos with a modified FLIR E4 camera able to deliver an IR resolution of 320x240 (76,800 pixels).
The hottest part is the DC-DC converters. We apply a high load on those rails during these tests, to check their behavior since in the majority of cases the manufacturers don't use beefy heat sink in these regulators.
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