Geforce 250 GTS and Radeon HD 4870 compared with old vs new drivers
 

To be honest, we expected much larger differences, especially as the time gap between the tested drivers is pretty big. Once again, we had very specific situation here, comparing pretty different graphics processors. The one was the old model while the other was yet to be proven, and it managed to do this job, and after a year and a half it is more than capable to perform in almost any game. Therefore, the advice of keeping the video drivers always up to date, which can be heard in the circles of enthusiasts, should be taken with caution: depending on the generation of card you use and the games that you play most often, the gain in speed will often be indistinguishable, and it's not impossible to see a performance drop. It could be wise to save some old driver packages that you know they are working properly, and to chase new drivers only if you play the latest games.

http://www.insidehw.com/Reviews/Grap...e-drivers.html