problems with Asus A7V266 (VIA chipset) & GeForce FX5700

[d3v]

Hi,
i'm running WindowsXP SP2 on a
Thunderbird 1333Mhz / Asus A7V266 with VIA chipset
256MB Kingston RAM @ 2-2-2
i changed gfxcard to Leadtek WinFast A360TD 128MB (GeForce FX5700 chip)
AFTER i had uninstalled old gfx drivers. After that i installed the latest nvidia 71.89
display driver and the latest VIA 4 in 1 drivers (with AGP Driver) for my
motherboard (BIOS is up to date), but still the gfx output looked strange. After i
disabled AGP Fastwrite in BIOS the gfx ouput is as usual, but in 3d games the card
doesn't work correct, showing me pictures like i'm drugged.
Anybody got an idea?