Probably the most demanding task a home computer preforms is rendering 3D games. In some case the GPU (Graphics Processing Unit) can outperform the CPU on the motherboard.
Here is a list of Link to some Graphics Card Benchmark programs.
Benchmark test using DirectX11
Unigine Heaven DX11 Benchmark
Futuremark 3DMark 11
Benchmark test using DirectX10
Futuremark 3D Vantage
Benchmark test for DirectX9
(Dude! If you are still using DirectX9 for your gaming needs go back to playing Farmville or Freecell on your computer)
Benchmark Stress Test
(This test has temperature data as well)