So far 12.6, 12.7, 12.8 give negative scaling in 3-Way Crossfire,
These are my 3DMark Scores, I did a fresh install before each test, installed the drivers i was testing + 3DMark 11
Look at the Graphics Score on each of them.
Windows 8 with 12.8 Drivers - Took ages to install these drivers, kept crashing after installing Catalyst install manager
3-Way Crossfire
2-Way Crossfire
Windows 7 with 12.8 Drivers
3-Way Crossfire
2-Way Crossfire
Windows 7 with 12.7 Beta Drivers
3-Way Crossfire
2-Way Crossfire
Windows 7 with 12.6 Drivers
3-Way Crossfire
2-Way Crossfire
Windows 7 with 12.4 Drivers
3-Way Crossfire
2-Way Crossfire
I haven't checked any before 12.3, but I'm very disappointed with AMD, I've only ever used AMD/ATI Graphics cards in my main gaming rig, next time I'll probably go with Nvidia.
And we won't be able to update to Windows 8 and play games until AMD decides to sort out their shit.
Intel i7 2600k (Stock for 12.4) (4.8Ghz for 12.6, 12.7, 12.8 )
G.Skill 8Gb 1600Mhz
Asrock Z68 Gen3 Extreme7