Was finding in last few weeks game had become unplayable.
I tried adjusting all the graphics options and found lowering the frequency under graphics options made a big difference. I lowered it from 85 to 70 and real improvement. I tried 60 but that flashes non stop and did my head in.
I found this had a bigger effect then screen resolution, effects, anti-aliasing, rag dolls etc. Might be just my set up no idea - but worked for me.