Most driver comparison focus solely on 3D gaming and / or application performance. Why? Well, for one thing, they're easy to do - make sure you use comparable systems / settings, run a few benchmarks with the previous drivers and then the new one and, voila, you're done. Drivers are an integral part of a graphics card performance. No matter how good the hardware is, if the drivers can translate design into performance, it won't work. However, there's so much to drivers than just performance. Stability, compatibility and usability for example. In addition to performance, usability is the next 'easiest' thing to review.
Check it out over here.