Return of Reckoning

Okay, so since about the time the last patch hit I can't do any PvP anymore. The reason is that I crash to desktop after a short period in fight. The location doesn't seem to matter SCs, open RvR as well as keeps fights are affected.

This is what I have done so far
-Downloaded the client again
-Disabled all addons
-System recovering to a date where the game was running stable
-Effects limited to warband
-Cleaned out the inventory to a state where the game was running stable
-I play in bordless windowed mode by default

Does anyone have any suggestions what else I could try? Because this is really getting frustrating.