This affects Civ2 and ToT. Under Windows 10 the performance of the game seems to sometimes be incredibly bad. Just moving the viewport of the map takes up to 2 seconds to show the new terrain. The cursor blinks more slowly. The units move slowly. This seems to happen randomly, maybe just for some saves. To be clear, nothing is going on, it's not like the AI is performing their turn. Is this problem known, and what is a possible solution? (Other than to downgrade to Win7 which never had those problems.) I read somewhere that it may be related to the game using outdated DirectDraw libs, but surely an improvement for that should exist, since it should affect all older games that use it? EDIT: MY SOLUTION I fixed it by setting compatibility mode and disable fullscreen optimizations! Civ2: Compatibility mode for Windows 7 - no videos but at least the game works ToTPP: Compatibility mode off - everything as it should be It seems windows tries to switch the game to fullscreen in a loop, which doesn't work because it's a windowed game and this causes performance degradation.