i have the same issue. Do the new update and the new drivers fix this issue?
Alright, I tested 361.43 driver and it didn't do anything, it is still broken beyond belief. The graphical glitches are totally out of control. The textures on terrain disappear randomly and you are able to see through the planet with all crazy pieces of the terrain floating around making it very disorienting, not to mention the horrendous performance. SLI-mode is not working right as it doesn't boost your FPS at all, in fact it's making the game perform even slower. I'm aware that I'm using dated GPU's, but I should be able to get much better framerate.
I for now force the game to use alternate frame rendering mode 2 in the nvidia control panel. It works.
This new driver and the hot patch has brought the second GPU of my 690 back into play. As soon as I reloaded and saw 3 figure FPS in the hanger I knew I was back to pre-horizon performance. Still can't get away with Terrain Detail on Ultra (about 15 fps) but High works fine (could only play with low and everything else max'd before this update). Still get some fps drops that last a second and the first time I tried to look at a surface map it took a good 30 seconds to load for some reason, but otherwise really pleased with the new driver/hot fix.
I tested Windows 7 too. Same glitches are there too.