I just upgraded to Cat 5.2 last weekend, and my frame rate improved significantly (max is around 85 fps). Previously I had been using only the Dell-approved ATI drivers.
Am using a 1-year-old fancy Dell PC, however. Not sure what older hardware would experience.
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Dell Dimension 8300
Pentium 4 3GHz
256MB DDR ATI Radeon 9800 XT (AGP), driver Catalyst 5.2, AA & AF on "sw control"
SoundMax Integrated digital audio, Analog Devices driver 5.12.1.3650, "std" hw accel
1024 MB RAM
Windows XP Pro, regularly updated from MS website.
DirectX 9.0b
Desktop 1024x768 pixels, 32 bit color
Aces High max texture size 512, 1024x768 pixels
Norton Internet Security 2004, all updates
Norton Antivirus 2004, all updates