Overclocking G400 to get higher refresh rate on second display? Please how?

[Kuja]

Hi everybody,

I'm running two monitors on my G400.

Primary is 19" at 1280X960 85Hz.
Secondary is 17" at 1152X864 85Hz.

I wanted to replace secondary 17" for a 19" and run them both at 1280X960 85Hz.

Then I discovered that for secondary monitor I can't go higher than 75 Hz at 1280X960.

I understood that this could be solved by overclocking.

But I would like to do it as little as possible, I just need to get that refresh rate on secondary monitor.

Is there any step by step guide for totally unexperienced people like me? At some site I saw some "pins" or something like that, and it totally freaked me out!!!

Before this, I was totally against overclocking in any way, since I prefer stable computer to fastest possible one. But I don't feel like changing my G400 for G450 or G550 just for 10Hz difference.
On the other hand, that difference means a lot, since I spend from 5 to 10 Hrs a day in front of my computer working in Photoshop!

Thanks,
Aleksandar

[Kuja]

It's me again.
After doing some more searching I came to conclusion that It has to be done in BIOS, no software utilities, so that it is
permanent.

At various sites I've read about BIOS pins, but there was no info for the beginner. What pin is for what, what their values represent and in what increments they should be changed?

My card is G4+MDH4A32G 906-4 rev.B model. I don't know what the memory speed is. Can it be derived from model nuber?

Thanks again!

Aleksandar

[Kruzin]

I have heard of people o/cing the primary RAMDAC in the past (I've done it myself), but never the secondary.
I'm not entirely sure it's possible.
If it is possible, you would need to know the exact line in the PINs to modify. A quick look at various sites with PINs info has turned up nothing for the secondary RAMDAC.

"PINs" is basically a dump of BIOS info into a regular text file that can be modified, then reloaded into the card's BIOS. Many people have modified their PINs to make their G400 into G400 MAXs (or somewhere inbetween).

The originator of such BIOS "hacking" is GBM's site, where you can find what lines of a PINs file affect what on the Gxxx cards, including an alternative BIOS dump/programing program:

http://grafi.ii.pw.edu.pl/gbm/matrox/

Unfortunatly, I did not see anything there that would affect the secondary RAMDAC...

[Ashley]

Try changing the values at offsets 44 and 45. The default should be 34 (decimal) for 34MHz * 4 or 136MHz. For 1280x960x85Hz, you'll need a 150MHz dot clock so increase the value from 34 to 38.

(I have no idea if Powerdesk actually uses this value as a ceiling.)