Originally Posted by
Jofm5
You want seperate rails if your going for a new power supply.
Most of the ones I've tinkered with didn't have separate rails: they looked separate, but all went back to the same point on the PSU board.
The only time you really need extra connectors is when you have one of those gamers' graphics cards that pull more current than a slot on the motherboard can provide.
I keep a couple of 550 watt ones in the cupboard to fix family and friends' machines when they go bang.
It's usually the PSU cooling fan clogging that makes it overheat and die. I hoover out the CPU and GPU fans (and any others) when I change the PSU, and often take off the CPU heatsink and wash it. I put it back with some thermpath, and usually that sorts everything.