My system: AMD 2100+, 512 MB RAM, VIA KM400/A chipset.
I've tried this with both 8762 and 8756 drivers without any differences.
I began trying to get the nvidia drivers to work on my 2.6.17 kernel. After installing the drivers, I couldn't get more than about 10fps in Savage @ 1280x1024. I am using Debian/sid with Xorg 7.0. I installed the drivers under /usr/lib/xorg (not /usr/X11R6). glxinfo shows direct rendering enabled and matching client and server versions from NVidia. I was using AGPGART and dmesg showed:
agpgart: Detected VIA KM400/KM400A chipset
agpgart: AGP aperture is 128M @ 0xe0000000
agpgart: Found an AGP 3.5 compliant device at 0000:00:00.0.
agpgart: Putting AGP V3 device at 0000:00:00.0 into 8x mode
agpgart: Putting AGP V3 device at 0000:01:00.0 into 8x mode
However, /proc/driver/nvidia/agp/status showed that AGP was disabled. I tried recompiling my 2.6.17 kernel twice -- once with agpgart and via-agp enabled and once without either of those. I booted each of these kernels with each of the values "1" through "4" for NvAGP in /etc/X11/xorg.conf. No combination of kernel configuration and NvAGP settings enabled AGP.
I downloaded the source for the 22.214.171.124 kernel (this was the last kernel I remember using with AGP, with my Ti4200, about a year ago). The 126.96.36.199 kernel enabled AGP with either AGPGART or without it (according to /proc/driver/nvidia/agp/status). However, my frame rate is still excessively low. While running glxgears, my CPU utilization is constantly over 90% (yes, I know glxgears isn't a benchmark, but I couldn't get Savage to run in a window, with top running over it, and still see the FPS because it the FPS was pushed off the bottom of the screen). The only high CPU utilization problems I could find in these forums or elsewhere on the Web was related to direct rendering being disabled, but direct rendering is enabled (glxinfo gives the same results as described above while under the 188.8.131.52 kernel).
The agpgart messages in dmesg don't appear until I load X. This isn't surprising to me, but I'm mentioning it in case it is significant. If I reduce the resolution to 1024x768, the FPS in Savage roughly doubles but still stays under 25fps. The CPU load is the same at both resolutions. My Samsumg SyncMaster LCD doesn't support any other resolutions (at least not with my X server). The nvidia-settings tool shows that I am not tied to vsync. I've tried to edit os-registry.c to manually force the card into AGP 4x mode by setting ReqAGPRate = 7. I've also tried to set EnableVia4x = 1. Both of these changes were fruitless.
I'm fairly sure that the low frame-rates are due to the high CPU usage. I'm completely lost as to figure out what is causing the high CPU usage though. Is there a way to be sure whether a certain process is using direct rendering or if it the glx module or nvidia driver is using the AGP accelleration?
I've attached my nvidia-bug-report.log file.