"no signal input" after 1hour usage??

[Beddall]

hey,
I have developed a new problem with my computer that I was hoping you guys might be able to help me with.
After about 1 hour of playing games on my pc the monitor will shut down.
If I press the power button on the front to restart the monitor, I get the message "no Signal Input"
shortly after this the computer will usually reboot itself. ( but not always)

As I say, this only happens when I am playing games, which leads me to believe that It could be related to the Gfx card being under a heavy load. (gfx card = Nvidia 9600gt)
I checked the GPU temp though and that barely reaches 54 degrees, which makes me think it can't be under that much strain.

So I was thinking maybe that it could be a PSU problem, and that maybe the computer is shutting down power to the Gfx card. could this be likely?

all fans on the computer are relatively dust free and spinning normally.
I have checked the computer temperatures with CPUID and everything seems normal apart from something called a Winbond which is running at 128 degrees ( But i think this may be a false reading as it never changes from that... ever)
I have tried both sockets at the back of the Gfx card and the problem happens in both.
The Gfx card does not appear to be loose in it's socket, though I haven't pulled it out and put it back in yet.

so, anyone able to shed some light on this or pass on some advice?
any help at all would be greatly appreciated.

cheers

[Whiternoise]

I had an issue similar to this last christmas (on an 8800GT). I would load up Fallout 3, play it for a while and then after an unspecified amount of time (sometimes it didn't do it), the screen would go black and say that nothing was plugged in. The computer itself was clearly still running (or attempting to run) although the sound glitched and looped.

I tried changing my fans, logging temperatures and like yours - well within safe limits. I assumed it wasn't my PSU because the system could do plenty of CPU heavy activity without batting an eyelid. I tried driver updates and even an OS re-install (i installed Windows 7).

Now, the interesting part was that if it happened in Windows 7, the computer didn't just die. It seems Microsoft found a way to isolate the system from the graphics card so that it would just switch back to the desktop and give an error message - i forget exactly, but it was something about the graphics kernel failing. So, clearly a graphics card issue rather than a power supply one.

The only way i could find to solve it was a new graphics card, i'm afraid - it hasn't happened to me again since.

My advice would be to first, see if your card is in warranty and send it off detailing the error. Failing that, graphics cards are getting cheap cheap at the moment so it's a good time to upgrade!

[peterb]

If the PSU was shutting down, it is likely to shut down the whole machine, not just the GPU card.

Although the symptoms point to the GPU as being the failing part, it could be a memory issue, so I'd run memtest86+ as a first off to check out system memory.

Does the problem occur with all games? Does it happen if you run one of the system stress programs, such as Prime?

[Whiternoise]

When it was happening to me, it was basically anything that stressed the GPU slightly. Some low-graphics games weren't affected (i seem to remember being able to play OpenTTD, Diablo 2, etc fine). However, more recent games like Titan Quest, Fallout (mentioned) all crashed out. I did try running the GPU version of folding@home too, that crashed it as well.

The memory i have now is the memory i had then, and it's still ticking over nicely. But, there's no harm in checking it before you shell out on new kit.

[Beddall]

hey,
That thing you said about the sound looping and stuff sounds exactly like what I have.
It's a shame as the card is less than a year old so i guess it should still be in warranty.
Gonna try running 3dmark on it to see what happens there.

cheers for the replies guys.

[Beddall]

hey,

I ran 3dmark and everything was fine. monitor didn't lose signal or anything.
So I tried the game again... after 5 minutes the monitor lost signal.
so I tried a different game ( Bioshock) that I thought would put a bit of strain on the Gfx card... everything was fine.
So I tried the original game again (Neverwinter Nights 2) and after about 5 minutes the monitor lost signal again.
Is it possible that it could be some compatability problem with this one game? that seems a bit odd to me but I don't know much about these things.

Is there any chance that something else could be causing this? like my MoBo soundchip or anything?
Might sound a bit silly but i just want to check.

I tried to run the memtest thingy but not sure what I'm doing with it. I don;t have any writable media to write the boot files to :S

thanks again for any help you can put my way