http://pcgamingwiki.com/wiki/Crysis_2#External_TV_locked_at_24Hz
Basically, when playing Crysis 2 on my TV (which my computer is hooked up to via the HDMI on my graphics card), the game was locked at 24Hz, and the workaround listed on that page only sometimes worked.
For anyone who had this problem on Crysis 2, has Crysis 3 solved this?
Thanks