This has been an issue for a while now.
I launch GW2, play for varying amounts of time, and then the game just freezes and stops responding. Also, occassionaly, the AMD graphics driver would crash when all I had open was the game client.
This is the only game that this happens to, which is a shame considering this is the game I play most often. I have tried using the latest beta drivers, which make the problem seem more frequent, and am currently trying the CCC 14.2 driver which made the problem go away at first, but now it seems to have come back.
Graphics card: AMD Radeon HD7870 (XFX)
Catalyst driver: have tried 14.7, 14.4, 14.2
OS: Windows 8.1 64-bit
Motherboard: Gigabyte H87N-wifi
Power supply: XFX XTR 650 watt
CPU: intel core i5-4670 LGA1150 3.40 GHz
11:51 PM by