So i upgraded my psu yesterday to a 750 watt one so i could sli my two 9600's. And now when ever i enable sli i can start a game and play 30 secs of it before it crashes my computer. Could it be my mobo is just so far out of date. I have a 650i its like 3 year old tech. What do you guys think.

Did it work before you upgraded the psu? And if you never tried sli with the old psu hers your chance.Pay no attention to the watts they recommend just try it.Rails are much more important than watts.

who makes the psus?

Try running with each GPU separately, see if it's one or the other that's causing the problem. Is there any error that comes up? Install latest drivers? Enable SLI in the mobo and in bios (sometimes an option)? How are your temperatures?

yeah, the psu could be overheating too, or the sli could be overheating your mobo.

and define "crashes my computer." does it freeze? does it hang up before it crashes? do you get the blue screen of death? tell us what happens.

Or the PSU could possibly be rated at a much lower wattage with a higher label slapped on it.

I once bought a PSU from Xoxide that was rated at 750 and when I got it I started having all sorts of problems. I got a buddy to help me test the thing out thoroughly and it turned out the PSU only had a max of 250 and they just slapped a 750 sticker on it.

QFT

Does it only crash when you play a game? Playing games heats up everything in your computer and the addition of a 2nd vid card adds a lot of heat!!!

I have one 8800GTS and with the stock cooler it was idle at 60 Celsius and 80 peak load.

Ok the psu is a 750 watt Tt Tough power. I have had my comp on for the last 3 days and 48 of them hours it was doing a stability test and i just got home and gpu 1 is at 40 and gpu 2 is at 45 that's with it being on for 72 hours. And yes it only crashes when i play a game. Also if i don't have sli enabled then its fine and the temps stay the same so i don't think its a heat problem. I have 5 8cm high rpm fans plus a 12cm fan in te back so there's air moving in the case. I have a zalman CPU cooler on it so the the Q6600 dont go above 40 eather. Um i made sure all the wires are plugged in all the way on both sides of the cables cause its modular. all i can think of is the mobo maybe the bios is out of date but i don't feel comfortable flashing them myself so i might have geek squad do it again to see if that helps. It might Yellow_Flash_Colorz_PDT_43.

yes, could be the mobo and bios, but it also could just be the psu overheating from pushing the extra wattage for the 2nd gpu. not really sure how to test that :(

http://www.newegg.com/Product/Product.a ... 6817153038

This is what i bought at my local computer store but for 30 bucks cheeper. It could be the psu is over heating but im not sure how to find the temp for that one.

Check to see if there is a bios update for you motherboard.Its not impossible that sli is broken on your board.Although i doubt it.Also are you powering your motherboard at all the available places to hook up the psu.Reason i say this is my motherboard has a optional 12v plug [i think its 12v,don't hold me to that]that you use only if you overclocking or running it in extreme ways.

Check everything all drivers,all connections,bios,Dx and what everyone forgets motherboard drivers.You would be surprised at how many pc's are running without having the mb drivers installed.

my machine went through 2 thermaltake 700watt psu's before i went out and bought my 1000watt. i always thought thermaltake had a good reputation, but they didn't work out so good for me. then again, my problem was complete psu failure, not crashing only during gameplay.

So i updated my bios it was only out of date by 2 versions but Ive played cs:s and cod4 with sli enabled and no problems have accrued yet. So i think that fixed it. I'm so happy so very happy today.