I recently installed a new PSU and GPU and now whenever I play a game it will run fine for 10 minutes and then crash showing a blank screen. I'm not sure what exactly is wrong. The CPU temps are 30-40c while idle so heat is probably the problem, but I've also gotten a cheap generic PSU so perhaps i'm not getting enough power? Or perhaps the drivers? (although i've updated my GPU drivers to the most recent)
Specs: Q9400 Quad Core
4 gb DDR3 Ram
MSI 5770 HAWK
720 Watt Ritmo PSU
Win 7 64 bit Ultimate
Cheap Case with a single Chassis fan as the back of the case.
What do you mean exactly by crash? Does it lock up, turns off, gives BSOD, crash to desktop or automatically restarts? Does it crash only while gaming?
If you only have one fan you could be overheating, play a while and monitor your card with EVGA Precision or RivaTuner, if you see heat rising you can manipulate fans to work to 100% and see if the crashes still occur.
I don't know about your PSU, 720 watts should be enough for your system, if the unit is actually capable of delivering them, but you'd need a multimeter to check that.
Another possible culprit is the RAM, is it running at the recommended timings and voltage? You can check that on CPU-Z in the SPD tab and configure it on your bios.
Well, when the game (any Game) freezes, it'll lock up and the image will turn into 3 stripes of colour ( Red, Green, Blue) or will just disappear and leave a 'No signal' message. and the sound will playback the last second repetitively. Forcing me to restart.
Sometimes old drivers won't uninstall completely and their remains can cause all kinds of problems. Also, make sure you remove any possible trace of Nvidia driver, in case your motherboard has a GeForce onboard GPU. If it does, disable onboard video from your bios too.
That CPU does seem to be overheating, since it's maximum safe temp is 71.4 celsius.
The usual fix would be cleaning all dust from the PC, removing the heatsink/fan, cleaning the old thermal paste from the CPU with isopropyl alcohol 98% or a similar substance, and then apply new thermal paste.
Also you may consider getting a new case with more fans and better air flow or buying a better cooler for your CPU.