I'm going to kind of give a back story to help explain my issue, if you want to get straight to the point, skip everything up until the "Here:", but reading the full post may help answer any further questions you have, or help you answer my question.
Hardware I'm questioning the integrity of:
AMD Phenom(tm) II x4 965 Processor 3.41 GHz
EVGA GTX 570 (I think it's factory overclocked but not sure)
I've had my computer for about 3-4 years now, but got my GTX 570 about 6 months ago.
So, I recently have been getting back into making gaming videos for Youtube. I was getting frustrated that Windows Movie Maker would crash my computer half way through processing a 4-6 GB video clip, in addition to randomly turning off while I was playing graphically intense games. So, I removed my side panel to notice that there was a lot of heat emulating around my heat sink and CPU.
I downloaded CPUID HW Monitor, and was shocked to find that my CPU has been getting in an upwards of 90C under load. I've never been one to know much about hardware; my dad helped me build the computer a few years back, but I researched what I could do to lower the CPU temp.
Finding that I had old Thermal Compound, I used ArctiClean 1 and 2 to remove the old compound off the heat sink and CPU, then I think I used Arcticsilver 5, made sure that I didn't use too much, and carefully reattached the heatsink back to the cpu. [FOR THE RECORD: I did not notice any physical burn/damage marks on the CPU when I cleaned it]
After testing my results, I was happy to find the temp on my CPU would cap at around 55C under a heavy load, and only get to around 50C at the most processing videos.
However, my computer continued to crash randomly during games. I checked my GPU's temp to see that it was getting around 65-85C during games. I looked around miscellaneous forums to mixed results, some people said that temperature was fine during gaming, others said they didn't like having their own cards getting that high.
So, using EVGA Precision X, I turned up the fan speed on my card from 40% (I think that's the default stock setting) up to 80%, then monitored my temperatures in game. The temp would only go up to about 65C, which is considerably safe (apparently) for a video card, but this still did not stop the computer crashes.
Here: I've made sure that all the wires I disconnected to apply fresh thermal compound to the CPU were fully plugged in, I've dusted every component in my computer, and the temp monitors are not showing signs of anymore overheating, so that can't be the current problem.
I made sure not to use to much thermal compound, and that it did not leak over the sides when reinstalling the heat sink, so I don't think that could be a possibility either.
When the crashes occur, my monitor goes black and loses signal (as if the computer turned off), however, my computer and all the hardware inside is still on. The only difference that occurs inside the computer is the video card will revert to 40% fan speed if I had it set to 80% when I was gaming. The power button on the front of my computer does nothing to turn off the computer, so I have to manually switch off the power supply by crawling under my desk and hitting the kill switch. I give it like 20-30 seconds, hit the switch back on, then am able to use the front power button on my computer to boot it up again.
Now, I might have had my CPU running at temperatures between 70-90C for a COUPLE YEARS. But, I can freely do anything else I want on my computer without risk of a crash, they only occur when playing graphically intense games.
I've made sure that all my drivers are up to date, but it hasn't made a difference.
And, like I explained in my story, my computer currently does not reach unsafe temperatures under a heavy load.
So, what I'm wondering is if there is any way to check if it might be a damaged CPU? And if not, or if that's not the problem, what else might it be?
Games where crashes have occured:
Saints Row 3
Dark Souls: Prepare to Die Edition
Skyrim (wasn't crashing before, but just did a day or two ago as I was testing)
If there is any other information on my computer you need to know to make an assessment or suggestion, please let me know, as I am not an avid forum poster or hardware expert, so I'm not sure what else might be a contributing factor to the issue.
Thank you in advance for whatever advice you can give.