ASUS M3A78-T AM2+/AM2 AMD 790GX HDMI ATX AMD Motherboard
AMD Phenom 9950 Agena 2.6GHz Socket AM2+ 125W Quad-Core
G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500)
ASUS EAH4850 TOP/HTDI/512M Radeon HD 4850 512MB
COOLMAX RM-850B 850W Power Supply
Thermaltake Armor+MX VH8000BWS Black Aluminum / Steel ATX Mid Tower Computer Case
Windows 7 Premium 64 bit
Shortly after I installed Windows 7 (I previously had windows Vista 32-bit) I noticed my computer would be fine one second and just blank out the next. The screen would go blank, it would not respond to any inputs but the fans and lights inside my desktop would still be running. I know its not the monitor just blanking out because when I reboot I get notices from windows that my machine was not properly shutdown and any sound coming from my speakers cuts out. It also does this sometimes while the machine is booting up after I get the BIOS logo and before it gets to the OS so I know its not Windows 7.
I've been thinking it has been the RAM but I ran prime95 for 24 hours with no failures so that has made me think it might not be the RAM, although I know that prime95 isn't perfect and the ram could still be suspect.
Awhile back I had a bad power supply that would force me to turn on and shut off the PC several times before it would boot. I wonder if doing that has caused something in the motherboard or CPU to fail prematurely.
Any ideas, thoughts or suggestions would be greatly apprecaited.
If you haven't done so yet, run download memtest86+ and put it on a bootable CD. Let it run overnight to be sure there's no inherent problems with the RAM. This will be more thorough than P95, whereas P95 tests load conditions. http://www.memtest.org/
Correct, I tried each stick alone and I tried each individual stick in all 4 memory slots. I noticed the other day when I first check the ram modules that I had placed them in the two memory slots directly adjacent to the CPU. The airflow from the CPU blows directly on the RAM modules.
I'll try some new RAM first and see if that fixes it.
Another update...I tried a single DIMM last night; I booted into Memtest86+ and I let it run. My PC has been shutting down after about 5 minutes in Memtest86+ but about 30 minutes later I checked and it was still running. Lo and behold that single DIMM ran all night and my PC never shut down. I think it completed something like 8 full memtest cycles in aboug 10 hours and I never got a single error.
I'm going to see tonight if I can do the same thing to my other DIMM....If its not the RAM then I guess it could be the CPU, MB or PSU.
Okay, I think I finally have this resolved; it appears to be my video card.
I kept trying to test the RAM but I would get inconsistent results. Finally, I tried 1 stick of RAM at a time in the A_1 slot. Ran memtest for 12 hours...no errors. Tried the other stick, ran for 12 hours...no errors. However, even with only 1 stick of RAM in my computer was still blanking out every so often so I was thinking at this point it was the Motherboard (since the RAM was coming clean in memtest).
I was 10 minutes away from ordering a new MB when I decided to check my video card. I pulled out my 4850 and switched over to the Radeon 3300 that my motherboard has built in. Well, I left it on all day, no crashes. I put both sticks of RAM in, left it on all day, no crashes. I finally have spent the last 2 days running 30+ hours of memtest no crashes.
The final test was ARMA II. I had noticed that when I tried to start ARMA II and let it sit at the menu screen (which renders naval and air assets from the game engine as the background; pretty good test for my 3D hardware) it would crash within 5 minutes or so everytime.
I tried ARMA II with the 3300 and even though it was like watching the slideshow (I had ultra settings enabled) it never crashed. I left it running for 10 hours and it never crashed and I haven't had a single problem since taking out my 4850 card and using the onboard 3300.
I have a new 5850 black edition on order and I'll get it sometime this week so I'm hoping this resolves my issue.
Glad to hear you found the cause. Any chance your GPU was just seated too loosely? Also do you have the latest drivers? AMD had some issues with Windows 7 x64 they were shaking out, for a while last fall there were new drivers every two weeks. Latest is mid-December: http://support.amd.com/us/gpudownload/Pages/index.aspx
I reread your thread this morning and picked up on the fact that you described the problem as the screen going blank a couple times. Certainly sounds (in hindsight) like a loose connection or bad power, or just bad hardware in general. I was more curious about the drivers than anything else.