I know I'm not replying to the right post here, but didn't see another way to post on this thread so...anyways.
Rukky and I were talking the other day on vent and he mentioned having some serious issues running gw2 on his geforce 560Ti(gw2 installed to SSD - 30sec freezes, long load times, etc.) while running other comparable games perfectly fine.
I'm kindof a driver freak, so I did some searching around and found that a lot of other geforce card users were having similar problems. Found a post on guru3d.com with some drivers(306.02 Beta drivers) that are supposed to do the trick. You really should frequent this site - great resources.
The link is for the 64 bit drivers, the 32 bit link(if you need) is up towards the top.