Well, I can only talk from my own experience. My first card was an Nvidia Geforce 2 MX. While the card was not that powerfull, I found that the support was great. I worked with every game I bought and the drivers were superb.

Now I've upgraded my PC and switched from Nvidia to ATI. While my new card (Radeon 3D 9700 Pro) has awesome power, I find that support in games for ATI is much less. SoF 2 single player works well, but textures of water often are displayed incorrectly (as a black and white matrix). Sof 2 multiplayer is not playable at all. I just get some sort of wireframe. Only the character models are displayed correctly. I know this is caused by the OpenGL drivers, but at least you'd expect ATI to update their OpenGL drivers for Windows (we all know Mickeysoft won't do it because the're only interested in pushing DirectX).

Another example is BF1942. It runs very smooth, but occasionally you can notice a 'bar' running between two buildings. If you move a bit closer, the bar dissapears. It's just a small clipping bug, but is shows that developpers still focus on Nvidia and less on ATI imho.


ATI drivers on the other hand have finally come of age. No problems here (I've been told that wasn't always the case).

The good news is that things are starting to change. ATI is gaining momentum. Not only does it currently holds the fastest gfx chipset in the world (while in the past they were always second to Nvidia), but if now companies like Mickeysoft are turning to ATI then you can be sure that support for ATI is only going to improve.

Well, there is a reason that most games are tuned to nvidia...
nVidia offers much more support to game developers then ATi, and nVidia itself is the inventor of many graphics algorithms.

Just take a look at the nVidia developer page and you'll see what I mean