I did catch up on the enb website, that folks were having good resulst with the ati preview 12.2 drivers in combination with ENB and antialiasing being activated.. so I decided to tried it out...
I am using realistic Lighting 2.3 + Enhanced Shaders on a 965 Phenon II 3,6 ghz. Ati 6950. Everything Ultra. x2 antialiasing, 8x anisotropic... and FXAA on. Shadow medium
On the highest point on whiterun, worst angle I was getting around 30 fps. Now I am getting at least 34.
So, If you want to try them out
http://support.amd.com/us/kbarticles/Pages/Catalyst122Previewdriver.aspx
This are, preview drivers, so use at your own risk obvisouly

tell us your perfomance changes on that one ! =)
It may happen that it only boost skyrim if you were already using enb.. non enb players may or may not see a boost on perfomance.

