I ran across this last month.

Make sure you have xsrc of at least 2000-01-13 (otherwise you will have
to also apply the patch in pr xsrc/9171).  Then use

Option "xaa_no_color_exp"

in the Device section of your XF86Config (where you tried "no_accel"
before).  I've been running like this for a few weeks now, and it's not
noticably slower at 1600x1200x32bpp than the Mach64 machine sitting next
to it running at 1280x1024x16bpp.

This info should probably be added to the NetBSD X Window System FAQ list,
as it probably applies to anyone with a Rage 128.

(I also submitted a bug report to xfree, but haven't heard anything back
from them.)

jdarrow

-- 
John Darrow - Senior Technical Specialist               Office: 630/752-5201
Computing Services, Wheaton College, Wheaton, IL 60187  Fax:    630/752-5968
Alphapage: 6303160707@alphapage.airtouch.com            Pager:  630/316-0707
Email:     John.P.Darrow@wheaton.edu