So finally did a little FPS test on my Asus Radeon 5770 (WinXP Pro, Athlon II 435 X3, 4GB DDR2 5-5-5-15 Corsair Ram, Sounblaster Audigy 2ZS, Biostar-mainboard,..) on Mugello track in free-practice mode, 32bpp 1920x1080, no AA with some ATI drivers. Here is the (my) ranking:
2. very closely followed by v10.07
3. v10.08 (also quite good, as a first impression I thought the picture/textures were more clear here somehow)
5. v10.05, v10.10(bad) and v10.12 (with this three I discovered the worst performance)
Sometimes they do not differ much (0-5 FPS), but especially v10.05 and v10.10 deliver the lowest average FPS.
v10.06, v10.07 and v10.08 also seem to deliver a slighlty more smooth moving.. of the trackside things where I noticed this when the picture moves left<->right, so in other words: when you're steering.
So the v10.06 which I already used all the time before was/is already the best choice, ..so all the testing for 'nothing'
regarding to gain more FPS by using another driver -lol-.