Everyone loves Windows 8. So it comes as a real shock that the newly released Windows 8.1 is causing issues with mouse lag and cursor jumping in some PC games. Games said to be affected are Deus Ex: Human Revolution, S.T.A.L.K.E.R.: Call of Pripyat, Metro 2033, and Call of Duty games.
Games that don’t use Raw input for reading mouse movements are the ones suffering, as something has changed in how Windows updates pointer positions. This Reddit thread reporting on the issue contains a sort-of fix that reduces the problem in some games. Hopefully it’s something Microsoft will address quickly.