This is why GPU Drivers Might Not Matter [Hardware Canucks]

This is a great look at a number of games over time from launch to months after launch benchmarking the patch releases as well as drivers. The end conclusion is the day 1 drivers that Nvidia/AMD/Intel produce are worth having and they improve performance and fix bugs but later drivers don't show as helping and the performance changes after that point are attributable to the game updates.

What is wild is Baldur's Gate loosing a tonne of performance in a patch and has never recover its prior performance and it can't utilise the GPU at all well now but there are other games showing not just increases but degradation of performance as well.