Woohoo!
After fiddling around for about two days trying to figure out why this
KT133A board's AGP write performance totally sucked compared to a KT266
board right next to it, and after going through _every single option_ in
the BIOS to find nothing helped, I've finally figured it out!
(Incidentally, this is an MSI K7T Turbo KT133A (Athlon XP 1800+) with an
ATI Radeon VE, not a G400, but having exactly the same problem.)
I was fiddling around in powertweak and found "CPU to AGP posted writes"
under Hardware / PCI / VIA Technologies, Inc. VT8363/8365 [KT133/KM133
AGP] / Tweaks. This option was disabled...when enabled, "dga" times went
from this:
Framebuffer write speed: 61696K/s
Framebuffer read speed: 16334K/s
To this:
Framebuffer write speed: 138304K/s
Framebuffer read speed: 16334K/s
...And, x11perf -repeat 1 -shmput500 (and -putimage500) went from:
320 reps @ 15.8666 msec ( 63.0/sec): ShmPutImage 500x500 square
200 reps @ 26.3183 msec ( 38.0/sec): PutImage 500x500 square
To:
800 reps @ 7.1125 msec ( 141.0/sec): ShmPutImage 500x500 square
320 reps @ 17.2638 msec ( 57.9/sec): PutImage 500x500 square
Also, changing the option cured a problem I was having with my bttv card
(bt848) where overlay mode would show interrupted scanlines transferred
from the bttv card to the AGP video card, but would work fine to my PCI
video card. (It looked like each scanline was getting randomly
interrupted, causing the right side of the window to rarely be updated
while the left side was working fine. Increasing the PCI latency on the
bttv card helped a little bit, but did not cure the problem. It seems to
be working perfectly now!)
Now if only this chip/motherboard would idle as did the older chips with
the HLT instruction...
Simon-
[ Stormix Technologies Inc. ][ NetNation Communications Inc. ]
[ sim@xxxxxxxxxxx ][ sim@xxxxxxxxxxxxx ]
[ Opinions expressed are not necessarily those of my employers. ]