I meant to use another PSU with the additional drives. Since they are connected only through the datacables it doesn't really matter that the voltages aren't exactly the same (I think). I think I will try it (or at least research on that) myself some time.
You may still have current running through the IDE cable I'd think. If the 5V on the drive, and the 5V on the cable are not the same...
I have a system with two CPU's which are 76°C to 77°C "warm" (always), if I can trust gkrellm and actually the BIOS too. So 48°C shouldn't be a problem at your side (I guess).
Yeah, that's what's really bothering me. Even my BIOS tells me the temperature isn't above 55C when I reboot right after a lockup, so I think I can trust gkrellm. It's possible that the rising temperatures outside have pushed things over a limit I didn't encounter during the winter, but then still 55C is ridiculously low. Perhaps it really is the temperature of the drives, which unfortunately I cannot measure. Regards, Pieter