Video Card Failure Symptoms
First off, thanks to PlayTool Home
for the images. They have some awesome stuff to do with PC diagnostics, and I really recommend checking them out.
Disclaimer: I do not intend to steal any material from Playtool, I am merely using some of their content in explaining some symptoms of video card failure.
When your video card begins to die on you, there are many symptoms, so much so that it can be hard to track down where your problem lies. Sometimes it can be as simple as configuring some stuff in your BIOS where as some other problems might require a new card altogether. Either way, this guide should at least give you some pointers as to what the problem is and how to fix it.
The easiest way to discern a monitor problem from a video card problem
The easiest way of telling if your monitor or your video card is experiencing problems is by simply switching monitors. I know it sounds really stupid, but the amount of people I see blowing money on new hardware without even diagnosing the problem is ridiculous
Video RAM problems
Video RAM works a lot like RAM you find on your motherboard: it holds many different types of data (textures, polygons, etc) that will then be accessed by the GPU shortly after it has been stored (again, a lot like normal system memory). Normally when this part of the system goes bad, you'll see the effects in both 2D and 3D mode:
Video RAM holds data known as the frame buffer, which is basically used to store copies of the screen that are still being drawn by the GPU, or in the case of a static image, the final copy of the screen. Here a small portion of video memory has failed where the frame buffer is stored, causing an overlay of red dots, since the GPU is trying to render wrong data which it is reading from the failed memory. Windows Vista and Windows 7 may exhibit slightly different symptoms at the desktop, due to their use of 3D mode in the main user interface.
Here is an example of video RAM failure in 3D mode (while playing Half-Life 2: Lost Coast):
An image on the screen is made up of combined red, green and blue at different intensities to create a certain colour. Sometimes when this data is stored in failing video RAM some or all of these colours can go missing. Notice how in the village above the sky has an overly yellow cast to it in places, as a result of a certain colour being missing (in this case, blue). You may have also noticed the amount of spiking in the image. When a 3D model is rendered by the GPU usually it is done by calculating the difference between the vertices on the shape. When the wrong values are read back from memory, spikes and other artifacts can occur, demonstrated in the amount of spiking in the village.
Here is another image of a common graphical artifact as a result of failing video RAM: random spots all over the place. If you look on the door you can immediately notice the white spots (and if you look to the wall on the right, you can also see the black dots). This can happen in both 2D and 3D mode, and when this symptom does exhibit itself there are usually many more dots than shown in the above image.
How do I fix bad video RAM?
Unfortunately, video RAM is usually soldered to the PCB of your video card, and is not by any means replaceable by the end-user, unlike standard system memory, which is socketed. Sometimes, backing off on your overclock (if you have one) may help the problem. Sometimes There is, however, a ray of hope if you are gaming on *ahem* integrated graphics, because usually integrated solutions share system memory. Usually if you see these kinds of symptoms all you need to do is replace your system memory (to find the bad module use Memtest86+ to test each individual stick to find the one that's playing up) however if you bothered to shell out on a graphics card your only option is to RMA it or just take the opportunity to upgrade
The GPU is the main chip on your graphics card which does all of the rendering (as you hopefully already know, after all it does stand for graphical processing unit) and it's usually very rare for it to completely die. Here is an example of a GPU-related problem:
As you can see by the obvious tearing issues, only parts of the image being drawn, etc. it's quite obvious something is up with the GPU. A problem with the GPU is usually quite easy to tell apart from a video RAM failure, so usually if you discover it it's quite easy to know what exactly went wrong (useful for overclockers)
How do I fix a GPU problem?
This time, your options are not as limited as when a RAM failure occurs. Note that it's very rare for an actual hardware GPU problem to happen (and even when it does, the card is usually stone-dead) so if it does happen, you can check to see if your GPU's fan is running (if you have one, that is) since after all it's main job is to keep your GPU cool. You could also try replacing the thermal paste (or if you want to get your hands and your warranty dirty, the fan itself) since GPU-related problems are normally caused by heat. Again, if you have an overclock, then back off on it (this is why I'd recommend a motherboard with CMOS profiles).
Warning! The following information is obsolete! This will only be a viable solution if you still use AGP!
Sometimes AGP graphics cards can store data on the system memory. When the data is fed back to the card, it can become corrupted, making the symptoms look very similar to video RAM failure. When this happens usually all you need to do is reduce the AGP multiplier a notch (e.g from 8x to 4x). If this doesn't help, it may be time for a new motherboard
(well, let's face it, you probably need the upgrade as it is)
Thanks for reading my guide, people! I hope to get a sticky on this one, despite me being completely new to the forum
And again, great thanks to PlayTool for the images, go check them!