Since the release of DirectX 8.0 graphics cards have used programs/instructions known as Shader Models to help interpret instructions on how to render graphics sent from the CPU to the graphic card. Many games are increasingly listing Shader Model versions in their system requirements. However these shader versions are tied to the version of DirectX that you have installed on your PC which is then in turn tied to your graphics card. This can make it difficult to determine if your system can handle a certain shader model or not. To determine the version of DirectX you have running:
1. Click on the Start menu, then "Run".
2. In the "Run" box type "dxdiag" (without the quotes) and click "Ok". This will open up the DirectX Diagnostic Tool.
3. In the System tab, listed under the "System Information" heading you should see a "DirectX Version" listed.
4. Match your DirectX version with the Shader version listed below.
Once you've determined the version of DirectX running on your PC you can use the below chart to determin what Shader Model version is supported.
Please note DirectX versions prior to DirectX 8.0 do not support shader models
DirectX 8.0 - Shader Model 1.0 & 1.1
DirectX 8.0a - Shader Model 1.3
DirectX 8.1 - Shader Model 1.4
DirectX 9.0 - Shader Model 2.0
DirectX 9.0a - Shader Model 2.0a
DirectX 9.0b - Shader Model 2.0b
DirectX 9.0c - Shader Model 3.0
DirectX 10.0* - Shader Model 4.0
DirectX 10.1* - Shader Model 4.1
DirectX 11.0* - Shader Model 5.0
DirectX 11.1*† - Shader Model 5.0
*Not available for Windows XP OS
†Only available for Windows 8 OS
One recommendation prior to installing a newer version of DirectX is to ensure that your graphics card supports that version of DirectX.