I have a phenom ii x6 1090T, 6950, and 4GB of ram. I am also running catalyst 13.2 Beta 6.

The single player runs more sluggish than the multi player. What I found strange was that although I set everything to Very High, it would say Custom in the main menu when I reset the game. I fondly remember this from Crysis 2 when AMD made some kind of optimizations. I also seen it in the beta.

It seems like there are optimizations in place for the MP over the SP. Also when I edited a few settings in advanced graphics in the MP, I went back to single player and the shadows setting was listed as "Custom"- the single player actually played better after dabbing a bit in multiplayer. I think AMD, and Crytek dropped the ball- but there are some apparent software issues.

The FIRST level has a bug in it. When I set it to Very High, Psycho has a glob of texture, tesselation, and just **** all on his torso. If you get close to that blob, the performance shutters hellishly. When your away from the blob, the performance is pretty good. The jungle level right now, I am playing at 1080p with Very High on. Sure, its playing around 30FPS, but its actually playable.

So short summary:
There seems to be optimizations in place for the Multiplayer.
The first level bug with Psycho kills performance, other than that it isn't too bad in later levels.
Some things need to be fixed, this reminds me of Rage in terms of performance with AMD stuff.

Ok the bug on Psycho is on other levels too, and whatever effects and shading techniques that are on him slow the game to a screetching halt.

The bug is only active when you put the Graphics on Very High.