Do NOT use the 6052 drivers.
I had massive slowdowns using the 6052 drivers, the game was nearly unplayable.
I just tried the 6043 rev. 2 drivers and the game now runs very good with all details at Max (even Texture Detail at very high!!!). Outdoors it is not totally smooth in 1024x768, but in 800x600 it runs really great!
The Volumetric Shadows still screw up the lighting though... (I hope this will be fixed in a patch or a new driver)

My System:
Athlon 1 GHZ
Asus A7V Mainboard (Bios: 1010A)
512 MB PC 133 RAM
ATI Radeon 64 ViVo (Drivers: 6043 rev.2)
Soundblaster Live Value
Plextor Plexwriter 12/10/32A
Creative DVD-ROM
IBM 30 GB Harddisk
Windows XP