I (used to)have a P4HT 3GHz w\ 512MB RAM, ATI Radeon 9200, 1 CDRW drive, 3 IDE hard drives of sizes 13GB, 40GB and 80GB, and one 200Gb SATA hard drive, along with 2 case fans all running on a Turbolink CWT-420ATX labelled 420W max with the following max DC output specs:
This system ran without a hint of trouble for about 4 months, except for a couple spontaneous reboots which I'd long forgotten about. A couple days ago, while copying some gigabytes from the 40GB drive to the 80GB drive (with the Win2KSP4 running on the SATA drive) windows complained that C$Mft was inaccessible, then I heard some hard drives turn off, then I got a blue screen saying the login process was terminated, then I rebooted. I wasn't able to boot from that drive. Upon examining the situation using another Win2K installation, I found out that the system partition on the SATA drive had disappeared. I thought it was some software problem, so I conveniently restored the partition from a backup. While trying to do the same copy operation, the system rebooted without any warning this time. Again looking at it, I saw that this time the other (~170GB) partition on the SATA drive had disappeared. (Fortunately nothing terribly important was on it)
Only then I suspected the power supply, and disconnected the SATA drive to reduce the consumption. While looking around on the web for help, I had the system reboot on me once again, with only 3 drives connected.
Right now I have Gigabyte's motherboard monitor utility telling me the +5V rail is +5.24V and the +12V rail is +11.79V. I tried disconnecting and reconeecting 2 more drives and a few fans, but the voltages never went more astray than that.