Sis 630 graphics under Redhat 8.0

How to start...

I own a Sis 630 graphics chipset in a Samsung laptop, runnning under redhat 8.0. I have scoured the internet using google dozens of times, but still I'm not quite happy with the graphics on my computer!

The best site i have found so far is:

http://www.winischhofer.net/linuxsis630.shtml

which goes into a fair amount of detail, but still it preforms nowhere near the performance of it under WinDoze...

That isn't the problem i'm asking about though (I wasn't expecting it to work as well under Linux), the thing I want to ask about is why it becomes jumpy under the latest kernel released for RH8 (kernel-2.4.20-13.8). some of the screensavers are even jumpy, and tuxracer is down to about 1fps!! Under kernel-2.4.18-27.8.0 it can at least do the screensavers... is this a bug in the new kernel or should i recompile and change options (gulp!!)??

Thanks for any help you can give...
Fish