I've got a 570GTX. I'll drop down the LOD effect and see if that's the culprit.
There are many settings in there, I gave the ones that work with me. With that in mind just do a bit of testing to see what suits you best. It's easy to overlook a value there since there are so many options that you can tweak so take a closer look.
Make sure "Antialiasing - Behavior Flag" is set to "None
"Antialiasing - Mode " is set to "Override any application setting
"Vertical Sync" set to "Force Off