Sehh, could you specify which modules you removed?
This problem sounds somewhat similar to mine (here)
except that you're not getting the badness messages. I'm also using the ASUS A7N8X - Deluxe. It was more noticable with my 5200 FX than with my Ti 4200.
Harshy, did you try the NVidia AGP module instead of the kernel AGP driver?