View Full Version : Possible bug in PD5

14th August 1999, 10:58

I think i've found a bug in the new 5.13 powerdesk.

It all started when i put a p3-450 in my PC, my G200
started to show random pixels under the cursor, and
then locked up after 2 minutes. Also my G200 got VERY
VERY HOT!!!!!!!
Well, after much hair pulling i think i figured it out.

I installed the 4.33 powerdesk and drivers, but still
had the same problem. But theres a util knocking about
that enables hidden options in powerdesk. So i tried
turning them on and off until i saw positive results.

This is what fixed the problem for me:

In registry

[HKEY_LOCAL_MACHINE\Software\Matrox\PowerDesk\Curre nt Settings]
"Use Write Combining"="1" <<<<< i changed this to '0' and
all is ok now!!!!!!

That is, under version 4.33 it works. Version 5.13 must enable
it by default.

BUT how do i turn this off in 5.13 ??

I tried putting EXACTLY the same registry entry after installing
5.13 powerdesk, but it has NO effect ???

Where does it keep this setting, and indeed, all the others ???

I'm gonna mail Matrox and let them know, this was a real pain,
and has taken me about 3 days of tinkering to find!

B.T.W I have no problems when changing bus speed to 66mhz ??

Hope someone can help!!!



14th August 1999, 11:38
Hi again,

I FIXED IT http://forums.gagames.com/forums/smile.gif)))))))


[HKEY_LOCAL_MACHINE\System\CurrentControlSet\Servic es\Class\Display\0000\Settings\CPU]

heres where the little fecker is kept, they changed the name of it!

all the flag/key names can be seen if you load G200.drv into a hex editor and search for Combining

you'll notice they've got to be entered in seperate catagories now http://forums.gagames.com/forums/smile.gif

Matrox: GIVE ME A JOB http://forums.gagames.com/forums/smile.gif



14th August 1999, 16:12
I know what write combining does but is it supprted by the G200? The logical answer to that would be yes because they implement it in their drivers.

Im lucky I can disable it in my bios settings.

14th August 1999, 23:47

But does my motherboard ?

What exactly does it do ?


15th August 1999, 10:42
I don't know if you mothetrboard has that setting, maybe it's only on the P2-99 boards like mine.

It says in my motherboard manual that the speculative write combining can greatly improve the display speed by caching the display area. It's a new cache technology.

But one thing I don't know is if it's supported by the G200?!?