How far do you overclock your G400 with the Tweak Utility?

[Narayan]

Some 3DMark 99 scores:

G400 plain, 32MB 6ns

125/166 - 1024x768x32 2949, 1600x1200x32 1247
150/200 - 1024x768x32 3153, 1600x1200x32 1535

------------------
Currently powered by:
Celeron 400@500MHz, Matrox G400 32MB DH, Elite PBXT-A+, 96MB PC100

[mikechen]

I bought a G400 16MB DH yesterday and overclock it today
I use the MGAtweak, and really confused by all those options. I tried so many combinations, and found my SGRAM can't be over more than 183, guess that's because it's 6ns. Chip can be over to 150.
However... I can't figure out what's the difference on 3DMark! the fastest combibation was 133/177, which got only 0.5% increase (2814 / 2799, on K6-3-450) on 3DMark. All other combibation even get slower than normal.
I have some minor issues now, and I'm working to find out if they are caused by overcolcking or SS7 issues.

[mikechen]

Wow... I'm happy that someone see my post.
I forgot to mention that I run 3DMark 99, at 800*600*16bits double buffer, 16bits zbuffer.
The score it too low, isn't it? I guess it's because my main memory is running at 66MHz.
I don't have money to replace my 64MB older SGRAM (10ns, can't do 100MHz), but I really need them... a 64MB system isn't enough.
I tried to pull them out and make the other 64MB running at 100MHz, and I get a 1000 scores up.
And... there's still someone can run their G400 with 6ns SGRAM at 150/200! Can you tell me how you do that?! I just get a bad screen above 183. My card is made in China.
P.S. I live in Taiwan, and I rarely write in English. Forgive me if you think some sentences are strange
P.S.S. There are some empty places that I think there's should be some capacitor in back of the G400 chip. Are yours also be? I feel bad when I compare this with the picture on the magazine.

[leporis]

Hunsow hoe did you manage to do that? i´m very interested in that solution


Mine goes with no probs and no fan to 174/218
and this with out a fan, with one it goes to 182

174mhz about 138% of my original vanilla speed

[Picard]

What are the risks if we o/c the MAX far above its spec (i.e 160% using Matrox Tweak Utility)? Can it break the card or just make the MAX can not properly run?

Thanks for your response.

[Hunsow]

WARNING: USE AT YOUR OWN RISK! DO NOT EMAIL ME OR OTHERS. IF YOU RUN INTO TROUBLE YOU'RE ON YOUR OWN. YOU ARE RESPONSABLE FOR YOUR OWN ACTIONS, SO WHATEVER BAD HAPPENS IT'S NOT MY FAULT.<center> </center>

Allright this is how I did it.

Download the bios_104.exe update available on the murc website, and extract it to a bootable DOS disk, with no autoexec.bat or config.sys on it. You might also find the required programs on the matrox cd, in that case copy the directory on that disk.

Boot the disk.

Make a recovery disk with the makedisk.exe command, if you haven't done so already. I strongly suggest you do this, since you can repair any damage that might occur with just booting this disk.

Run "PROGBIOS -d >pins.txt"

Now you can edit the pin.txt file. In my case it looked like this:

;MGA Bios Programming Utility v1.94d
;(C) Matrox Graphics Inc. (1999)
;
Fill: 0 127 0xFF
;Matrox G400 AGP
;VGA Enabled - BIOS V1.5


0 2 0x412e
2 1 0x80
3 1 0xff
4 2 0x0401
6 2 0xc76a
8 2 2
10 2 0x0300
12 16 'LAD12345'
28 6 '402'
34 2 0x38a4
36 2 0xfff0
38 1 75
39 1 75
40 1 75
41 1 75
42 1 75
43 1 75
44 1 34
45 1 34
46 4 0
50 1 0x3f
51 1 0xff
52 1 0xff
53 1 0xc2
54 1 0xff
55 1 82
56 1 41
57 4 0x0190a419
61 4 0x24045491
65 1 126
66 1 63
67 4 0x019b8419
71 4 0x24045491
75 1 126
76 1 63
77 4 0x019b8419
81 4 0x24045491
85 1 0xff
86 2 0x0c88
88 2 0x0c88
90 1 0xee
91 2 0x2cfe
93 2 0xfff9

I could overclock completely stable upto 116.2%, which means a 146MHz GClock (126 default) and a RAMDAC of 348MHz (300 default). All you need to do is change the lines 38-43,65-66 & 75-76.
In the lines 38-43 you see the value of 75, for which you should read 300/4. So I changed it with 348/4 which is 87.
In the lines 65-66 & 75-76 you see the values of 126 and 63, which is the SClock and GClock divided by two. So I changed it with 146 and 73. By the way the first two are for 2D and the second two for 3D.

Now it looks like this:

;MGA Bios Programming Utility v1.94d
;(C) Matrox Graphics Inc. (1999)
;
Fill: 0 127 0xFF
;Matrox G400 AGP
;VGA Enabled - BIOS V1.5


0 2 0x412e
2 1 0x80
3 1 0xff
4 2 0x0401
6 2 0xc76a
8 2 2
10 2 0x0300
12 16 'LAD12345'
28 6 '402'
34 2 0x38a4
36 2 0xfff0
38 1 87
39 1 87
40 1 87
41 1 87
42 1 87
43 1 87
44 1 34
45 1 34
46 4 0
50 1 0x3f
51 1 0xff
52 1 0xff
53 1 0xc2
54 1 0xff
55 1 82
56 1 41
57 4 0x0190a419
61 4 0x24045491
65 1 146
66 1 73
67 4 0x019b8419
71 4 0x24045491
75 1 146
76 1 73
77 4 0x019b8419
81 4 0x24045491
85 1 0xff
86 2 0x0c88
88 2 0x0c88
90 1 0xee
91 2 0x2cfe
93 2 0xfff9

Now save it as "newpins.txt".

DO NOT CUT & PASTE THIS PIN FILE!

Run "PROGBIOS -i auto -s newpins.txt"

You probably have to press 'y' once to confirm.

Wait until you see the DOS prompt and then reboot.

[This message has been edited by Hunsow (edited 24 January 2000).]