au contrare, big dog, but i have an mx4000 pci, and it's a terrific card for playing links. i have no idea what world of warcraft might look like. but my mx4000 on a p4 1.8 w/ 1280 mb ram, is smooth as glass for links.
currently (as i change graphics drivers every coupla days), i'm using tweaksrus' xtreme-g 93.71s:
http://www.tweaksrus.com/index.php?option=com_docman&task=cat_view&gid=127&Itemid=41/
modded driver. i like the modded because i prefer image quality to performance, and most modders have a knack for accomplishing both. you can probably attain the same results yourself by using rivatuner, but i quit using rivatuner awhile ago simply because it was another program i had to keep up with.
the single most important trick to achieving success with any driver is to uninstall/install properly. guru3d.com has a great thread on howto install graphics drivers properly:
http://forums.guru3d.com/showthread.php?t=67799
anything else you need to know about the mx4000, let me know. i've done everything to it but desolder and reassemble mine.