Good power supply, stable voltage — Joe
SUMMARY: Not much variation under load.
The good guys at Antec were nice enough to send over a sample of their latest power supply series, the Antec TruPower 380. The difference, according to Antec, is that the 3.3 and 5 volt lines are separate – no matter how much you load up either rail, the other will not be affected.
On some power supplies, the 3.3v and 5v lines are shared, so that it’s possible to “rob” one line based on high loadings of the other. When I read this, I looked at an older power supply and found this:
Never really noticed it before.
First thing I did with the Antec 380 is open it up (if you do, you will void the warranty) to take a peek inside:
Good airflow pattern over the heatsinks, and two fans – cooling should not be a problem. Thinking about how to test it out, I went over to Radio Shack and bought 5 20 watt power resistors. My idea was to hook them directly into the 3.3v and 5v lines and see what happens while running Prime 95. I used the Shuttle AK31 running an XP @ 1463 MHz.
What happened was the resistors got very warm. I read the 5 volt line directly with a multimeter and used Motherboard Monitor readings for the 3.3v and CPU voltage:
| Condition | 3.3v | 5 v | CPU v |
| Idle | 3.22 | 5.00 | 1.73/4 |
| P95 | 3.18-20 | 5.00 | 1.71/4 |
| Idle 100w load 3.3v rail | 3.22 | 4.99 | 1.73/4 |
| P95 100w load 3.3v rail | 3.18-20 | 5.00 | 1.71/4 |
Not much variation. I thought the fans would speed up, but they stayed the same and the exit air did not feel any warmer under any of the above conditions.
Thinking maybe all power supplies could handle this, I tried it with a 300 watt older unit – it shut down as soon as the resistors hit.
I’m not a power supply expert, but I do know that loading this power supply had negligible impact.
Thanks again to Antec for sending this our way.
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