Overclocking GeForce 256: temperatures?

[lefou]

After I overclocked my Celeron (from 900 MHz to 1.1 GHz), I started searching for a utility to overclock my GeForce 256 videocard. I found a little smart program, that must work with most nVidia cards - RivaTuner 2.0:
http://www.actiontrip.com/files/util/rivatuner.phtml

Here are some results using 3DMark2001:

Celeron 1,1 GHz/122 FSB, 256 RAM@122 MHz, 4:4:1, 1.825 V

nVidia GeForce 256 32MB
D3D Hardware T&L
1024x768, 32bit
z-Buffering: 24bit
Texture Format: Compressed
Buffering: Double
FSAA mode: none

Feb. 15, 2002:
(Windows XP, original Windows XP drivers)
--------------
[core: 108 MHz/RAM: 143 MHz]: 3DMark Score: 1707
[core: 120 MHz/RAM: 155 Mhz]: 3DMark Score: 1864
[core: 125 MHz/RAM: 165 MHz]: 3DMark Score: 1977
[core: 140 MHz/RAM: 180 MHz]: 3DMark Score: 2175

As it may be seen, increasing the core/RAM speed leads to a better performance. But when I touch the chip when set to 140/180, I think it's very hot, not as hot as when at 108/143. If anybody knows, what are the safe overcloking options for nVidia 256 cards? May I damage the chip if overclocked from 120/166 (default) to 140/180. And any cooling ideas? I think the original fan on the nVidia card is not very good... it's even sleeve bearing, not ball!

Thanks!

PS The strange default setting 108/143 is, of course, due to the 122 MHz FSB setting, at 4:4:1, as when set to these values, the PCI bus probably works at 30.5 MHz and the AGP at only 61 MHz; and the default settings of 256 cards are 120 MHz/166 MHz AT 33PCI/ 66 AGP bus. Am I right?

[missiveusa]

You could add a different 60mm cooling fan on the GPU. Also, a sleeve bearing fan that fits in a PCI slot will give better cooling. The memory clock settings (the 2nd #) will realize the most performance gains, but will also cause instability if pushed too high. My Asus V 7700 has a probe. OC'd to 220/438 DDR from 200/400, it runs @ or less than 120 F.

[lefou]

I made various tests since then. Installed the nVidia Detonator 23.11 drivers; performance increased a bit. Here are some results:

Feb. 16, 2002:
(WinXP, nVidia 23.11 Detonator drivers)
--------------
[108/143]: 3DMark Score: 1903
[120/155]: 3DMark Score: 2074
[120/166]: 3DMark score: 2163
[125/165]: 3DMark Score: 2198
[140/180]: 3DMark Score: 2394
[150/205]: 3DMark Score: ==2613==

On 150 MHz core/205 MHz RAM I got the max results, with no system problems. When tried 165/215 and started 3DMark, the first frames of the test 1 were corrupt, so I immediately stopped all. I think something around 150/200 is the maximum, but now I run on 120/166 (default), for more safety, because I still have not a decent cooling.

May the GPU or the memory chips frye, when pushed up to 125% of their nominal values (for my card that means from 120/166 to 150/205)?

If anybody has any experience with the already a bit old nVidia 256, please, post a reply. Thanks!

Meanwhile, I appreciate very much the Riva Tuner 2.0. It's a very good program! And it helps me to get around this: my FSB frequency is 122@4:4:1, which means AGP at only 61 MHz, which means 108/143 MHz values on my card, instead of 120/166 (default ones for that model). Now I can set the values I want, no matter what's the FSB rate!!