So today when going to boot up my PC from sleep mode it didn't appear to respond. After attempting to turn the PC on and off, both on the PC itself and completely turning the power on and off at the back still no joy. The PC would boot up, fans spinning on both cpu, case and gpu etc but no video output. I tried resetting CMOS to no joy and then figured it was probably the GPU. Swapping out my Powercooler 6870 for an old 8800GT it booted up, albeit it had to recover some what from the cmos reset. Assuming I'd identified the problem i reset the PC to make sure it rebooted and it did. Just to be 100% sure it was the 6870 i tried it again and again it failed to produce a signal. Having safely established the problem i swapped back to the 8800GT again as a temp fix, however now i couldn't get a signal with that either. After a couple of reboots it sprung back into life. But its got me wondering if there's not another issue? Could it be say the PSU? Since the 8800GT has less power draw than the 6870 could it be my PSU (an Enermax 650) failing and only just producing the juice for the 8800? Or is there potentially another fault I've overlooked? I'm fairly confident its the 6870 at fault but would rather be 100% sure. Thx for nay help.
There is plenty of juice in the PSU to power what you have (unless you have 30 hard drives you aren't telling us about.) There is a good chance that it is failing though. How old is it? I can't find a 650w PSU on their website The GFX card is unlikely to be the cause as you stated that it did the same with the 8800. Stick the card in another system, anybody's will do as long as their psu is over 500w and a decent make. The gfx card doesn't use much power when booting, only when in graphical environments, apart from the initial surge when turning your machine on. Enermax are a reputable company, and should replace the PSU if it at fault as long as it is under 3 yrs old.
Faulty monitor cable perhaps? Although if it is a lack of signal maybe the contacts in the pci slot are iffy. Try blowing dust out of the slot with compressed air.
The PSU is around 3 years old, the Enermax Infiniti 650W was released autumn 2007. The problem only occured once with the 8800, but i tested it again this morning and it booted again fine. Which leads me to still think its the 6870 at fault. I may be able to test the 6870 at work to be 100% sure. If the GPU doesn't use much power when booting then that leads me to ssupect its a GPU rather than PSU issue.
