I have an old 4150 (8 core) on a Sabertooth motherboard (990FX chipset) with 8 gigs of ram and two 6970s in crossfire. Guildwars 2 runs fine for me, even in the crazy fights that erupt in the wild. When things get intense my gpu fans ramp all the way up and stay there until the fight is over, after that you can hear them ramp back down. This behavior is evident in all my games. When I am not gaming the gpus fans can hardly be heard. It may be the Nvidia driver doing bad things to you, try their forums and search for this problem...it would be interesting to find out if anyone else is having these problems.