What to look for if you're upgrading your video card:
- Do you have AGP or PCI-Express? Only recent PCs have PCI-Express, which is replacing AGP.
- SM2.0, SM3.0: This means Shader Model 2.0 and Shader Model 3.0. It describes the complexity and capabilities of the processing units on the GPU: SM2.0 is older and will not support High Dynamic Range lighting (HDR), as well as some other features. SM3.0 is newer and definitely something you should look for. ATI's cards that support SM3.0 are all of the Radeon X1xxx series cards, Nvidia's cards that support SM3.0 are the GeForce 6 and 7 series. ATI's X300/600/800 and Radeon 9xxx series (excluding 9200) cards support SM2.0 only, Nvidia's GeForce FX cards support SM2.0 only. Radeon 9200 and below, and GeForce 4 and below all support SM1.1/1.2 only and will not run Oblivion at all.
- Memory interface: 128-bit vs 256-bit: 256-bit memory interfaces can send twice as much data to memory per cycle, so are twice as fast. Memory bandwidth is important in video cards.
- Pixel pipes/shaders: The number of processing pipelines the video card has...the higher the better.
- Vertex shaders: The number of vertex processors the video card has...the higher the better.
- Memory: 256MB is the sweetspot right now, 512MB is more forward-looking. 128MB isn't recommended.