Incredibly long load times.

Last wednesday my ATI6850 gpu stopped working and I went out and bought an nvidia gtx550Ti to replace it. I now get appaling load times. Zoning into uldah it can be up to 60 seconds before player models display, doing instances like cutters cry the rest of my party can have half a room cleared before anything other than the background displays for me, cutscenes take up to ten or more seconds to load.
Only other change in my system is a new router but I've experienced no other internet related problems and speedtest shows no change in my ping or bandwidth from before.
Any ideas?

Figured out how to fix it. It appears to be that the nvidia card is a useless piece of crap. Put an ATI 6870 in and everythings fine now.