I've been having strange crashes with my recently assembled machine.
8GB memory (I've run mem test with no problems)
2 Hards drives
Sapphire HD6850 1GB
about 3 - 4 USB devices connected
Nothing is being overclocked.
The machine usually crashes while gaming (only seems to happen in starcraft 2), or watching flash video streams. Sometimes it will just crash without any high power demanding program at work. When a crash happens I usually get a "no signal" from my monitor and then only a hard reset will do (sometimes the screen can turn total white instead of "no signal"). Nothing appears on the Windows event log as this crash seems to be taking everything out in one fell swoop. I've also been having a couple of random BSOD's which according to WhoCrashed came either for kernel or video driver.
Now, the PSU I have is a no name brand with 1 12V rail of 27A. I've had that PSU for about 3 years and never had problems with it in my last system. My last card was a 8800GTS.
I realize that I need to change my PSU however before that I would like to rule out something like a faulty video card because it is still under warranty. I've never had PSU problems before (unless they just died) so I can't tell if this kind of crash symptoms are common with faulty PSU's. What worries me is that I cannot reliably reproduce the crashes. That, together with the fact that, from what I've learned, my last video card had about the same power requirements as my current one, makes me think that it might not be the PSU.
In case that I do decide to change the PSU, how many Amps am I looking to get (either 1 big 12v rail or two smaller ones?)?
EDIT: OK it just occurred to me how to reproduce the crashes and it worked. I opened up furmark and at the same time opened a flash video stream. Instant crash once the video stream started loading. Again, these crashes don't have a BSOD, it's an immediate black screen which only a hard reset can get out of.
PSU issues are difficult to confirm without substituting a known good PSU. You can determine how much power you actually need and the amps. required on the 12v rail(s) from the link below. You could probably use the Exteme/Severe load option in OCCT to test for a crash.