GeForce 9400 GT Pixel and Vertex shader confusion

I have GeForce 9400 GT made by Evga on my computer. Right now I am confused about the pixel and vertex shader versions. Whenever I try to find it on the net, I find this

"Unified Shader Architecture
Provides an effecient single platform consisting of vertex shaders, geometry shaders, and the pixel shaders. This allows for better performance and visual quality."

I am concerned about this because I'm unable to play certain that require pixel and vertex versions 3, and then I can play others that do. Example, my computer runs Left 4 Dead excellent, but then I can't run Mass Effect. Both games require pixel and vertex shader version 3. Any explanations and solutions? Thanks.

the gfx card you have, has only 16 shaders. ugrading to a 9600gt or an ATI hd4670 will bring a nice performance boost.

Each of your shaders can run vertex and pixel shader operation. They can also do geometry shader operations, but those are only in DX10 and since you'll be using XP you don't need to worry about it. Depending on what your playing you may have 12 shaders doing pixel shader work and the other 4 doing vertex shader work. By modern standards though the 9400GT is very weak and is not considered suitable for gaming, but hey it's your eyes you'll be scaring .