This has been happening to me for quite some time and I've noticed it only happens in Cyrodiil and usually when I get anywhere near a dolmen that is active or going active. I've filed numerous in-game reports and reports via the crash reporter, but I'm not sure if anyone else encounters this problem under similar circumstances. It isn't any particular dolmen, seems to affect all of the ones in Cyrodiil. I run win 7 enterprise with nvidia Geforce GTX 750ti, 8 gigs ram, 8 core AMD processor.