matiii wrote:
Hi,

I got Duron 700 on Gigabyte nForce2 GA-7N400 mobo (I know, $h1tty cpu
on good mobo - I'll buy a new one when I have some cash). I got myself
a better cooling and I want to overclock D700 to 1GHz, because AFAIK
now it runs in asynchronous mode with system bus 100, and memory at
200 (got PC3200).

So the reasonable combination seems 5x200, right? Correct me if I'm
wrong. Now, I have to unlock multiplier in Duron, so I've bought
conductive paint, I closed L1 bridges and I wanted to set jumpers on
mobo to 5x, then change FSB to 200 in BIOS. Unfortunately system
refuses to POST, when it has multiplier set to manual, so I had to
switch it back to auto and additionaly clear CMOS. The only exeption
is when I set multi to 7x (a default one in Duron), it works then too.

There's a couple of gotchas with the CPGA Durons (the ceramic ones, they go
"clink" when you tap em with a screwdriver ) and some motherboards. This
issue manifests itself as the board refusing to POST at any multiplier other
than the default one for the chip. For example, a friend of mine has an
identical Duron to you. He was wondering how high it could go, so I swapped
it for a spare Palomino I had lying around for a few days so that I could do
a few experiments. I rejoined the L1's and could set the multiplier to
whatever I wanted on my Soltek 75DRV5. I found a nice stable point on that
board, pinmodded it, Prime95'd it, and dropped it back off to his place. It
wouldn't POST on his motherboard (a Gigabyte as well, funnily enough).
Dropping it back into my board madde it work perfectly again.

So, I removed the pinmod and is began working (at the default multiplier) in
his board again. Changing the multiplier to anything but stock made it fail
to boot.

The problem is that the CPGA Durons (and TBirds, possibly) have the
multiplier set in TWO places: The L6, which tells the M/B what multiplier to
use, and the L1/L2/L3/L4 setup which tell the CPU what to use. Some BIOSes
check to make sure these are equal, and won't POST if they are different.
With the CPGA chips, the copper traces on the top are fakes. You can remove
them without damaging the chip at all (yes, this was verified on the Duron
in a rather unfortunate accident ...). The real traces are actually under
the ceramic, so you need a diamond drill to cut through them.

Alternatively, you can mod the motherboard to make it do multiplier
adjustments properly. As per usual standards, Fab51 has this fully
documented (albeit only in Japanese).
http://fab51.fc2web.com/pc/duron/duron1.html

With a 7x multiplier, you've got all the (important) L6's already pulled to
ground, unless you're wanting to go straight for a 11.0x multiplier (not
recommended). In this case, you either have to modify the motherboard (sever
the traces, yikes!) or get fairly brutal on the CPU (rip the pins off,
yikes!). I'd personally recommend you don't try either of these, and go for
straight FSB overclocking. With a 7x multiplier you won't have any problems
with the board not being able to handle the speed.


One thing that DOES puzzle me though is that you're using a fairly recent
board, but it doesn't do things correctly. My first step would be to set the
FSB back to the default, 100MHz, then try adjusting the multiplier to 6.5x.
If this works, then it's just the CPU not liking high FSBs or just not
liking the 1GHz you were trying to run it at. Try something a little lower,
such as 5x133 or 5x150. Also, you might want to try running the memory in
async mode which may give you a bit of a boost in in games.

[...]

--
Michael Brown
www.emboss.co.nz : OOS/RSI software and more
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