What could this video/display glitch be?

My PC is running Windows 7 64. All my drivers are up to date. According to device manager my graphic card is a Radeon 6800 series. I have updated all my codecs with the k-lite codec pack.

It started a couple of months ago, when I began playing Diablo 2. There would be a degradation in the graphics.

Then, later on, when playing simple windows games such as chess or hearts, I would get graphical artifacts in the form of checkering in random places on the screen. Opening a different window and moving it over where the checkering was, made the checkering disappear.

Just recently I have started to get artifacts when I am watching videos in “non-full screen mode.” These artifacts are like digital noise in the the form of horizontal lines.

I can consistently and repeatably get the artifacts to show up under the above conditions.

I have tried to take screen shots but the artifacts do not show up! This makes me think that there is some “overlay” setting that needs fixing.

I have read that it can be a sign that your video card is overheating but my video card is at 40c, very cool. All the temperatures in my PC are reading normal.

What could be causing this? I would like to explore possibilities before I get a new video card.

Unrelated to this, but you shouldn’t just wildly throw codecs onto a system. If you are missing a codec needed to play some media file, determine the missing codec and install it, rather than taking a shotgun approach.

The first thing I would check is to see if AMD has an updated driver (compared to what you’re running now) at http://www.amd.com (top right, “Support & Drivers”). Note that AMD moved to a “perpetual beta” model quite some time ago - official production releases are few and far between.

Windows Update / Microsoft Update tends to suggest inappropriate drivers for 'updates". If you have any non-AMD video driver updates showing in your update history, that might be the problem. In addition to providing sub-optimal display drivers, I’ve also had Windows Update completely trash my Bluetooth setup, and (longer ago) corrupt PCs into not booting, even in Safe Mode. Be very wary of driver updates offered by it, and check the manufacturer websites to see if they have a newer version instead. You can always check the “Don’t show me this update again” box, but it isn’t always “sticky”.

The second thing I’d suspect would be display adapter memory corruption. Note that this is memory on the video card, and not testable with things like Memtest86+. This could be due to an actual memory problem, overheating, or a power supply problem. You can stress-test your video card with FurMark to see if it can trigger the problem.

Overheating is certainly the most common cause of your reported symptoms. I would double-check your that you are looking at the proper temp as a first step. I would also suggest opening the case, cleaning all the dust off all the fans and heatsinks, and reseating the video card and its power connector.

As Terry Kennedy noted, it is possible that some previous incident damaged your video card’s memory or other area. Once you eliminate the possibility of heat, power, connection, and driver problems, that is what remains.

That’s strange. If you’re seeing problems on your screen during gameplay but not in screenshots, I’d double-check your monitor settings (refresh rate etc.) and driver. Do you have another monitor you could try?

Thanks for the suggestions. I will investigate all of them.

Well, I just did the Furmark test and it definitely triggered the artifacts. The temperature was fine though. It started at 39C and went up to 54C.

That means the buffer’s OK in memory, but not by the time it’s getting displayed. You can try other stuff first, but that’s 99% certain to be electrical: either the card or cords are bad, or there’s a loose connection at the monitor or card end. If you’ve checked the cheap stuff, it’s time for a new card.

The only other possibility I can think of is something electrical nearby inducing an actual current in the display cable, but that’s really unlikely these days.

Thanks everyone, for the help!

What make and model is your PC, many of the HP DV series are famous for overheating and separating their own solder joins. Fixing it involves heating motherboards until the solder will remelt and reconnect. We end up doing 2-3 of these a month. The term used is “reflowing” a motherboard.

I’ve only seen such behavior with video card overheating - CoH used to turn objects (like your avatar’s head) into a giant ball o’spikes when the GPU got hot. But if your readouts say 40C, that’s probably not it.