Falls ihr eine NVIDIA Grafikkarte besitzt dann solltet ihr auf jedenfall folgenen BluePost von Datth lesen:
"We're getting reports where users are getting intermittent low FPS after installing these drivers. It seems that it is related to the fan control included in these drivers not working correctly and is causing the video card to overheat on 3D applications. This will affect Warcraft 3, World of Warcraft and StarCraft 2 Beta. Please uninstall the drivers and revert back to the older ones.
Windows XP: NVIDIA DRIVERS 196.21 WHQL
Windows XP 64-bit: NVIDIA DRIVERS 196.21 WHQL
Windows Vista/7 32-bit: NVIDIA DRIVERS 196.21 WHQL
Windows Vista/7 64-bit: NVIDIA DRIVERS 196.21 WHQL
More information can be found on threads such as these:
Major with new drivers with my- 9800gt not oc - NVIDIA Forums
Problem with 196.75 driver - NVIDIA Forums"
World of Warcraft - English (NA) Forums -> Recent In-Game Fixes - March 2010 - 3/4
Wie ihr sehen könnt ist im moment die beste Lösung die Treiber auf eine ältere Version zu wechseln, falls ihr also auch diese Probleme habt meldet euch in dem Thread.