Here is some info on overclocking the Permedia2.  I have actually not done
it yet.  To tell you the truth it's working fine as it is.  I'm using it for
3DStudioMax and it works pretty well.  Well here it is...

Do a registry search for a key called "systemclock". This is a hexadecimal
number representing clockspeed. Some Permedia2 driver installs create this
key, some do not. Those that do not, will show your clock rate in system
device manager as being 80mhz. Most Permedia boards are at least clocked at
83. Without a heat-sink on the chip, and with standard 10ns SGRAM, 96mhz is
about as high as you can go. With a heat sink, and 8ns SGRAM (no boards
currently shipping have 8ns that I know of, although Hercules's 3D/GL is
supposed to have 8ns) you can go to as high as 125. Your mileage may vary.
if you do not have the systemclock key in your registry, you can add it.....
go to....
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Class\Display\000x\Defa
ult
the "000x" could be "0000" "0001" "0002" depending on how many adapters
you've installed without doing a clean windows install. You should be able   
to look in the different "DEFAULT" keys, and figure which is for your
current Permedia driver install. Add a binary key called "systemclock" then
modify it. Remember it's a hexadecimal number, so, for instance, "5a" would
be 90, "60" would be 96, ect.....
Warning! If you do go too high, and the system hangs, boot in safe mode,
edit the registry key, and reboot. the chip itself is pretty stable with
adequate
cooling to some pretty high clocks (as I said above, up to 125 theoretical,
with the right ram), so it's unlikely you'd damage the chip unless you get
crazy with your clock values. On a 10ns board, you'll be running into
bandwidth
problems at 96mhz or so........

Victor                    

Windows NT 4.0 SP3
------------------
Newsgroups: comp.sys.ibm.pc.hardware.video
Subject: Overclocking Permedia2
Date: 7 Dec 1997 00:50:02 GMT
Organization: EuroNet Internet
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Has anybody else experienced that ? I owe a Diamond FireGL1000 Pro, and
under NT4.0 SP3, altered the registry key
HKEY_LOCAL_MACHINE-SYSTEM-CurrentControlSet-Services-Glint-Device0-PermediaC
lockSpeed, and set it to 90 decimal. Went back to 83 decimal though, as the
gain looked marginal (11 to 12 fps in QuakeII test, everything on,
timerefresh at 1024*768 res., yes, not that many cards can have this res.
in 3D).
I didn't even have to reboot to do that, clicking on test in display
properties/settings after registry modification was enough. I suppose it
could damage the chip, so have to be cautious.
Just curious.      