You are likely using the mesa drivers. The way to get ATI drivers up and running in Mandrake 10.1 was a topic in another post
Here . Be sure to read the entire post and make sure you have all the requirements before starting the install of the ATI drivers. If you are comfortable in linux you should have no issues getting this to work.
The ATI drivers are the best to date put out by ATI. Good luck.
Just to give you an Idea of the improvment
glxgears in mesa drivers will run around 700 - 900 FPS
glxgears with the ATI drivers will run around 25,000fps to 50,000fps
If i get bored at work today i may post a How To on the subject.