first off the specs of my machine:
CPU: AMD XP 2600+ (non Barton)
RAM: 512MB "generic" DDR 266MHz
Video: Radeon 9600XT (4.12 CAT drivers, non Omega)
Sound: Chaintech AV710 with 1-12-05 referance ViA drivers
OS: WinXP home w/ SP2 (VIA CPU to AGP controller is using UAG35.sys driver)
MB: Giga-Byte 7VT600-RZ w/ F5 (latest) bios

I have not installed any VIA 4-in-1 drivers on this installation, I've tried various versions of them w/o success, i have Fast Writes and AGP 3.0 Calibration disabled, memory timings are non-aggressive, PCI Delay Transaction is enabled, I have enabled and disabled all those settings w/o any success. My system will not run any D3D game for any reasonable length of time, OpenGL however seems to run fine, only by disableing AGP w/ SmartGART feature of the ATI drivers can I run D3D games. One other curious thing, there doesn't seem to be any performance decrease that I can tell, I haven't run benchmarks on the games I 've treid, mostly Neverwinter Nights, but I've also tried Half-Life 2 and there doesn't seem to be any decrease...why would this be so? I've tried everything I can think of on the internet to get AGP working but to no avail, any other ideas of what it could be? thank you