High FPS cfg

My computer broke a few days ago, so now i am playing on a very poor quality laptop. I was wondering i someone could give me a cfg which could achieve the best possible fps with the lowest graphics while still being able to see the crosshair. I have all the graphics set to low with the resoloution at 640x480 but it is still pretty bad.
If no-one has a cfg then any extra console commands would be great too.
Thanks for your help.