I could be the wir size that you are running is to small. The contacts of the relay are smaller and are enclosed. The wire can disapate the heat fast due to its lenght and not being enclosed. Also a bad connetion on the relay will cause this. I have a atx with a amd 3.0 Ghz, 512 ddr, 12mb agp graphics, 3 monitors, wi/fi, gps, xm, and it all runs on a 250 watt dc-dc power supply. I can even let my truck sit off for an hour and restart the truck with no computer shut down. I do have 4 awg wire feeding the computer.