Arma 3 and Metro Last Light are graphically straining but also fairly well optimized. As if Battlefield 4 (well optimized but a crashtastic bug dump).
Almost all the other games here are as optimized as state funded education. Crysis 3 has some of the worst optimization of any game I've ever seen. --- -True knowledge is understanding why you truly know nothing. GT: "Avison Atrius" BB Mains: Hakumen, Arakune
Skyrim with mods probably (I haven't played it but I assume)
Serious Sam 3 I think. I have a i5 3570K @ 4.2GHz and a R9 290X and still in some places (very few places) the frame rate will drop to about 37-40fps. Game throws a crap ton of enemies at you. --- See The Game Collection http://people.ign.com/nights_team2k7/games