First post, by Sequencer
Or at least, this is the first time I've built a P3 system since the actual P3 era. At the time, I didn't have to put so much thought into it, since I could just buy things that were for sale retail at the time and have a fair assurance of compatibility. I'm finding now that power supplies on P3-era machines have become some sort of a dark art.
Firstly, I've already discovered that just putting your modern power supply on a machine like that isn't just overkill so much as asking for problems. (I found this out by doing it.) I'm running an Asus P3B-F, and the BIOS is complaining during bootup of, oddly enough, of too _high_ a -5V rail voltage: -6.1V
This is perplexing to me, since I've read that one of the problems with modern power supplies on older systems is supposed to be that they don't supply a -5V rail at all, much less one that has too much juice on it. I think I need some guidance on purchasing a power supply for this machine. I have found that the only power supplies on eBay that come out and actually say on their specs label that there is a -5V output are a few StarTech models. I've read here on Vogons that Delta and Enermax are both highly thought of, but none of them seem to ever mention this output rail existing or give their load limit for it.
While the CPU/motherboard/video on a P3 will surely not consume much power by itself, please know that I will also have a SCSI card, three hard drives, an ethernet card, and a SoundBlaster AWE64, so there is some peripheral load to provide for also. Do you think a StarTech 380W will be appropriate? Is the lack of any mention of a -5V rail on other non-StarTech PSU's a real problem, or is it nothing to really worry about? If the lack of mention of -5V output isn't any issue, there do exist higher wattage PSU's (~400-450W or so) from Delta and Enermax that I could be getting instead of the StarTech, assuming I even need more than 380W (which I'm not sure about).