Vista - Vista lockup problem

At random intervals, the screen will corrupt and 2-3 seconds later the computer will lock up, (see attached image). It will do this randomly when just browsing or using office, etc. And it can be a few minutes after startup or it can be a few hours. Games such as portal and audiosurf run without issue. Sometimes it'll do it once and be fine, other times it'll do it 2-4 times in a row. No logs or errors are being left in the event viewer.

During the running of the windows experiance index, it would do it during the running of the areo assessment until I update the drivers to 7.15.11.8120. Afterwards it ran fine, but the problem still occurs randomly. This was on a clean install.

I haven't overclocked anything on the system.

System information
Windows Vista Business 64
NVIDIA GeForce 8600 GTS
4 GB RAM
Intel® Core™2 CPU 6600 @ 2.40GHz, 2400 Mhz

The only upgrades I've made to my system is adding 4GB (was originally 2GB) and added another harddrive.



I've run memtest86+ which reported no problems.

Does anyone have any ideas what might be going wrong.
Edit: Windows Task Manager shows Physical Memeory to be 3325MB, not 4096MB

Have you tried using a different graphics card? The symptoms you describe and show in your image remind me of an issue I had with a Trident TVGA9000 card many years ago. The card would work fine, but attempting to switch to 1024x768 graphics modes would corrupt the screen and hang the system. This occured because the upper bounds of it's memory buffer where bad. Replacing the bad memory chips fixed the problem.

In your case, the graphics card may hav bad memory chips, or the GPU could very well be overheating. The best bet would be to try using a different card to isolate whether or not that is the problem...

I had thought of replacing the graphics card, but I don't have any spare. One item of information that may or may not be related, is Windows Task Manager shows Physical Memeory to be 3325MB, not 4096MB.

It sounds as you have a 32bit OS installed. This is the only reason I can see that you are losing memory. Try as Peter suggested and try a new card. This may fix both problems.

Hi Sparky,

This does indeed sound like your graphics card is getting a bit flakey. Check to see that the fan on the card is operating properly, and if necessary clean the blades carefully. As for your other problem, see this post: Memory issues with Vista64

I've checked out the memory issues, thread and tried everything it suggested, The memory hole setting in the bios reduced the ram listed in the task manager to 3324...

I'm definitely running 64-bit. I'll try and find if anyone I know has a spare graphics card I can borrow.

The fan on the graphics card seems to be working fine, don't think its a heating problem though since it can happen after just turning on the computer and after hours of use.

It's a common misconception that running a 32-bit OS is the cause of the "4GB Installed-but-3.5GB-is-Available" phenomenon.

Question: Can your motherboard support more than 4GB memory, or is it maxed out at 4GB? If the physical max is 4GB, then it likely is using a 32-bit memory controller. If you do the math (2^32) then you'll find the limit of 32-bit is 4GB.

When you first power up your computer, all the various devices are allocated (when needed) a block of memory. The memory space assigned to each device must fall within the 32-bit limit, and the space between 3GB and 4GB is the most common area allocated. Once this mapping takes place, the memory is "lost" to the system, hence the installation of 4GB, but only the availability of 3.3GB.

If your motherboard can support more than 4GB of memory, then it likely uses a 64-bit memory controller, and the memory assignments take place ni the upper parts of the 64-bit limit. In many cases, you'll lose maybe 1 or 2 MB of the first 4GB to the memory controller itself, in which it would place a memory mapping table for legacy 32-bit devices so that it can map 64-bit memory addresses to them.

So it does not matter if you are running a 32-bit or a 64-bit operating system. If you hardware is using a 32-bit memory controller, then you will have this memory "hole" that far too many people are blaming on Microsoft....

I believe its maxed out at 4GB, however the main issue at hand is the crashes, the memory gap was extra data that may or may not be related.

Running through all my drivers at the moment, making sure they're up to date.

Does you motherboard have an onboard graphics card that you can use temporarily? If yes, remove your 8600 GTS and check.

I'm still leaning to a bad graphics card.

What size power supply are you using?

350W dc output
It does have onboard graphics (after searching the BIOS to enable it).
rebooting now.