I just picked up a 2nd MSI GTX260 card and after putting it in, my system won't power up. The best way to describe it is that I hear the PS emit a short buzzing sound, the fans turn for a sec, then power stops. I suspect that I'm asking for too much power now, even though my PS is rated for SLI setups. I want to run it by the experts here before plunking down for a new PS.
I use the http://extreme.outervision.com/psucalculatorlite.jsp to find your power requirements -around 500w, your PSU should be able to power it with no problem. Try power up your system one more time -without the drives (except OS) and other non critical stuffs..see whether it powers on or not..
This sisverstone unit have 4 12volts rail rated at 18amps each. If everything is on the same rail ... NADA ! take the PSU use manual and be sure to use all the 4 rail to power the computer. seperate the load.
I'm going to say it's your 12 volt rails are faulty. Here is why, Minimum of a 500 Watt power supply.
(Minimum recommended power supply with +12 Volt current rating of 36 Amps.) This comes straight from EVGA's site on power requirements for the GTX260.
ok thanks for the input guys, it turns out I'm just an id-10-t. I removed the PS from the pc and realized I had another 6pin socket available but was hidden from view while in the pc. I was plugging the 2nd card into the 6pin Aux module which apparently isn't designed to handle the load of a gtx260. Moved my cable over to the other 6pin and am up and running in SLI.