Here is my problem:

I've Got Slackware 8.1 running on this "marginal" computer: K6-II + VIA Apollo 3 and a Trident 3D-Image975 4Meg AGP card. It is running Xfree 4.2.0 and works great doing 1024x768 at 16 bit color depth.

I loaded the latest KNOPPIX, which uses 4.2.1.1, and anything over an 8 bit color depth reverts back to a 4 bit color depth.

Here are some things I tried:

1) Using the Slackware XF86config file

2) Using the Slackware kernel

3) Using the fbdev instead

4) Using lower resolutions

5) Using the "trident_drv" from the Slackware file system.

In all cases I get the same results.

The /var/log/XFree86 log file shows no errors, and nothing suspicious except for a warning: "System lacks support for changing MTRRs" and a message at the top stating: "Build Operating System: Linux 2.4.20-k7 i686 [ELF]", (but it runs fine on my '486DX4133 + S3 video card).

I've had this problem before with this computer + video card combination, but what solved it was recompiling the kernel with VIA's GART support. My Slackware kernel now has this and works fine on the Slackware file system, but it doesn't work on the KNOPPIX file system.

Any Ideas?