It actually runs amazingly well, although it won't go above 1920x1080 maxed out.
Transgaming actually did a super job on this, and it has controller support for Xbox 360, ONE, PS4, and PS3 as well. Even on iMacs people have reporting really good performance.
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Only issue is that when you've sliced something up and it exceeds 50+ chunks, that's when I start to see an FPS dip. Most likely due to CPU physics.
Also Tomb Raider isn't that much of a resource hog on the nMP at all. The main issue is driver performance, although with Yosemite Beta 2 and up OpenGL 4 games like Tomb Raider, and Hitman Absolution got massive boosts in Minimum Frame Rates.
In Hitman alone my minimum FPS doubled in their benchmark. TR also uses OpenGL 4 like Hitman does in OS X, so a boost in performance is also expected.
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To quote the lead developer at Feral behind Hitman, and his statement of double FPS in the actual game holds true. I had no issues played the game maxed out at Ultra.
https://forums.macrumors.com/posts/19291231/
https://forums.macrumors.com/posts/19525504/