I would say that its from the latest windows update or game patch. (not sure which one)
But basically whatever video settings I use (from lowest to highest) it simply lags ... looks like hiccups, I just cant describe it well but what is interesting just an example lowest settings with vsync. So constant 60 fps / 50 ms latency and it dont change but it still doing this every few seconds (something like 3 - 6 sec sec - sometime its less visible and sometime its visible more)
I wanted to try public test server, to see if its working fine there but unofortunatelly its under maintanance right now.
The funny thing is that I tried morrowind on public test beta :-D and I bought morrowind and from that time its basically unplayable :-) Or at least its not really enjoying when I need to watch that hiccups.