Board Thread:General Discussion/@comment-26300350-20150411040930

So here's the situation. I have no problem running the game  with OpenGL fullscreen mode in win 8.1 but it's very unpleasant playing zombie mode with black fog everywhere. D3D is the solution to the black fog. But when I run cso in D3D fullscreen it lags like crazy. So I immediately switch it to window mode and the game runs flawlessly smooth with max settings. However, after a few minute in window mode an error pops up every time I try this and it force closes my game. This error never happens with fullscreen mode. So does anyone know a solution to fixing this problem of lagging in fullscreen mode? I would really appreciate any help :) 