also having this issue, never had problems before but now the client randomly freezes/locks up in lions arch or during the invasion event.
win 7 x64 pro
msi 7970 @ 1200×1920 high settings (also tried changing settings and it doesnt help the freezing problems)
8gb ram, 256gb ssd from which gw2 is run
all drivers are up to date and i;ve run the repair tool on the client which did not seem to repair anything and it still is freezing.