[Xorg] really slow X performance with Radeon 7200

[Anthony DiSante]

Hello,

First of all, I'm not sure if this is the right place to ask this -- if not,
please let me know where I should ask.

I'm running a Radeon All-in-Wonder (aka 7200) AGP on a Pentium III 850MHz
system with 512MB memory.  I'm currently running xorg-x11 version 6.7.0, on
kernel 4.6.3 (this on Gentoo Linux).  However, the problem that I'm having
also exists when I'm using my geForce4 MX 440 PCI card (64MB), and existed
when I was using xfree 4.3.x instead of xorg.  (I just upgraded to xorg last
week.)

The problem is that my video performance is really slow.  For example:

[0116][~]$ x11perf -shmput500
Sync time adjustment is 0.0665 msecs.
     800 reps @  12.1687 msec (    82.2/sec): ShmPutImage 500x500 square
     800 reps @  11.6212 msec (    86.0/sec): ShmPutImage 500x500 square
     800 reps @  11.7664 msec (    85.0/sec): ShmPutImage 500x500 square
     800 reps @  11.6915 msec (    85.5/sec): ShmPutImage 500x500 square
     800 reps @  11.7212 msec (    85.3/sec): ShmPutImage 500x500 square
    4000 trep @  11.7938 msec (    84.8/sec): ShmPutImage 500x500 square


A little googling reveals that most people are getting >200/sec and some 
 >1000/sec... I'm getting 85.

glxinfo reports that I do have direct rendering; I get ~900 fps with
glxgears at the default window size.

I can run 3D screensavers (for example the rss-glx ones), but they are
slow/jerky.

I do have mtrr enabled:

[0427][/home/falling]# cat /proc/mtrr
reg00: base=0x00000000 (   0MB), size= 512MB: write-back, count=1
reg01: base=0xf0000000 (3840MB), size=  64MB: write-combining, count=2
reg02: base=0xe8000000 (3712MB), size=  32MB: write-combining, count=3

So basically I've had this crappy performance for a long time, across
multiple kernels, multiple X servers, and multiple video cards.  I'd really
like to find out what the problem is and how to fix it.

Any ideas?

Thanks,
Anthony
http://nodivisions.com/

PS - I also just sent this message to the xserver at freedesktop.org mailing 
list, but then I read a message on that list saying it's going to be shut 
down any day now, and new posts should be made here instead.