Before patch 1.03 I was getting 50-60fps with a 50/50 split of medium-high settings @1080p. Now with all settings at medium I'm getting 40-55, seems odd given that this patch was to improve performance. Might just be my rig though.
Obviously I made sure to turn any nVidia tech off and not to use HBAO+ as they can really tank fps.

Win 8.1
i5 @4.2Ghz
8Gb RAM
MSI R9 280x

Performance has not changed for me, but since patch 1.03, I have crashed a few times.

Never crashed once before 1.03

i5 3570k
GTX 980 G1
16GB DDR3
Windows7 x64

Oh, pardon. 2 R9 290X working in crossfire.

Thank you very much.
Now I disabled crossfire, and according to Steam's FPS counter now I have proverbial almost constant 60 FPS. This is probably first game where crossfire actually lowers framerate.

My performance is better.

Anyway, whatever is your performance, that a better look into settings (even into file settings if necessary). Sometimes a patch can screw things up.