From: Collins Richey <richey@ecentral.com>

I had similar problems after install 2.3.

1) Don't try XF86Setup - graphics mode won't work
2) Use xF86config  - SiS 530 is in the card database, way down at the
end of the list.  All you need to tell it is memory size (mine is
8192).  Don't use clocks or probing.  Assuming that you can find the
correct info for your monitor, you'll be fine.  Select the SVGA driver.

My system is working just fine with SIS 530 onboard on a K862-300.