Aw hell yeah! Sapphire stuff is my favorite!
For sure I can list some FPS readings -
1) BioShock Infinite - 59.55 FPS everything on high except textures | 50 FPS (slight drop sometimes) everything on high (not ultra) | 40 FPS everything on ultra DX 11
2) Devil May Cry 5 - 60 FPS everything on max.
3) Devil May Cry 4 - 60 FPS everything on max.
4) Call of Duty Modern Warfare 3 - 59.55 FPS everything on high.
5) Call of Duty Black Ops - 60 FPS everything on high.
6) GTA IV - 60 FPS everything on very high.
7) Max Payne 3 - 60 FPS everything on high.
I can't think of more at the moment but one thing for sure, I can play every single game I throw at my rig without a single problem. Even if there is slight FPS drop sometimes in very demanding games like BioShock Infinite, You won't notice it.
Remember, we have have processors with negligible differences so our performances should not have big differences.
DX 9 and DX 10 games don't have that much differences, but DX 10 draws more power. Still in DX10 it squares off and even gets higher FPS in many games and have big differences in DX9. DX 10 improves lightening and shadows.
@OP - As far as I have seen a few games give you option to manually choose direct X. In DX11 Games I have not seen any performance compromises and I can play them all without any problem. It is one of the best mid range GPUs no doubt. This GPU struggles with 1440p displays but since you are at 1080p you are good to go.