Highest GeForce 256 OC

[ksoth]

I have a GeForce 256 (Hercules 3D Prophet DDR-DVI) that I have overclocked. I have it runnin at 137 Core/163 (326 DDR) Memory, using the new 6.50 reference drivers. I am wondering what the highest stable, safe overclock for this card is, and whether or not special cooling, RAMsinks, or anything else, make much of a difference. For me, moving the RAM speed any higher locks up 3DMark2000 and gives weird colored spotlights in games over the normal textures (Looks like a DISCO!!! 😛) Any help would be appreciated. Thanks.

 

[phsstpok]

If you are getting video problems you are probably past your limit and not every video card is the same. However, here are some things you can try. Since overclocking the memory provide much bigger gains than overclocking the core, you can sacrifice some core speed if it will give you more memory speed. The reason this might work is that the core generates <b>a lot of heat</b>. Enough heat to disrupt the stability of your memory. Try running the core at stock speed and see if the memory will run faster. Keep running benchmarks. See what combination will give you maximum performance.

As for cooling, I replaced my VisionTek Geforce256 SDR's fan with an old 486 fan and was able to increase my core maximum speed to 150 mhz, up from 145. I added RAM sinks but this did not increase my ability to overclock (210 mhz). What I did gain is where formerly, at max, I could barely complete the 3D Mark 2000 before crashes started. Now, I can now run for hours at a time at max (150/210). (I have to do this with the case open). I just recently learned of the suggestion at the beginning of this post. With the core at 120 mhz, I was able to run the video memory at 225 mhz but only long enough to do one demo in Quake III. I will keep experimenting.

In general, you are looking for your best performance that is completely stable. Then you want to back of from there, just a little, for insurance.

Hope this helps.

<P ID="edit"><FONT SIZE=-1><EM>Edited by phsstpok on 02/26/01 05:14 PM.</EM></FONT></P>

 

[ksoth]

Ya, right now the system runs great with no visual problems (except sometimes a little disco light here and there, but not nearly enough to be a problem). It's weird, cuz the lights appear only in certain spots, like the DUST map on Counter-Strike always in the same place... Weird. But running Giants demo, Alice, Starlancer, or anything else, there aren't any visual problems. You got your memory to 210??? Wow. Is the fact that mine won't go above 163 or whatever because it is DDR, producing more heat and therefore less stable at high speeds? Maybe RAMsinks will help with that? I think I have brought my core clock to like 145 or 150, but read that its really pointless because the memory is the bottleneck, so I keep it at a safer, low speed. Plus, I did run 3dMark2000 on it, and higher core makes no difference in my score. I think I'll try some RAMsinks, maybe make them myself or something.... Thanks for the info.

 

[Unolocogringo]

not all cards have the same same speed memory chips, older ones had 7ns and some of the newer ones have 4.5ns (lower is better) so not all cards will overclock the same.
also if your agp is overclocked,usually you will not be able to overclock as far as you would if your agp was running at spec.
even two supposedly identical cards with the same speed chips will overclock differently due to the slight difference in quality of all of the components on the card.

 

[Red_Zealot]

I got a similar card. Visual problems that I see when I push it beyond 245/280 (different cards are different, don't put your settings up to this)are: red lines on screen. Pulsing lights in UT. Green and red dots where they shouldn't be (i.e. the sky). If you don't see that, regardless of what you are doing, you're ok. If you start seeing that stuff, clock it normal, or just turn off the computer to cool it down. It might be worth the investment in a cooling solution, like a better fan or one of those PCI slot fans they sell at 3dcool.com. Good luck with the tweaking!


"If you teach a child to read, then him or her will be able to pass a literacy test" - George W.

 

[silverpig]

I had my CL Annihilator Pro at 165/400.
Funny thing is, I have an Annihilator 2 now, and the ram won't get much past 385...

Large cost increases for small performance increases can be tolerated only in race horses and women.

 

[jg38141]

I have a leadtek 256ddr running happy at 171/341 (170.5*2). I also have an asus6800 delux running 150/341. They both have copper heatsinks thermally epoxied to the chip, ram heat sinks and card cooler's blowing over them.. The leadtek will pretty comfortably run its ram at 371, but not without some artifacting and those little overclock specks one gets. The 171 core seems set in stone though. Although it has no problem running at that core, even up to 176 and it locks.


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[phsstpok]

Sorry, must have forgotten to click send replies to email address.

The SDR boards tended to have high quality fast memory because of the low bandwidth. Otherwise they would have been really slow. My VisionTek has 5.5ns DRAMs. The default RAM clock is 166mhz. I think DDR boards typically defaulted to 150mhz (x2=300mhz) but I am not sure.

As for RAM sinks, as I mentioned they only gave me stability at my maximum speed. I can run the video card longer at the max but that max is still the same 210 mhz.

A better fan will help increasing core speed. I use an old 486 fan with the original heatsink. It doesn't fit and is skewed but it works. I used wire-ties to secure it. Looks real ugly but I wasn't willing to pry off the old heatsink and risk damage.

I just made a mod on my system that had the side effect of allowing me to run max video speeds with the case closed. I upgraded my PSU to an Enermax PSU which doubled the current available for the 3.3 volt line. The new PSU has a second exhaust fan which gave me enough cooling to overclock my video card and motherboard to the same levels that I could with the case open. In case you are interested that's 150/210 for the Geforce256 SDR and my Duron is overclocked from 600 to 1007 mhz. (Actually that is not quite true, I leave the Duron at 950 and use SoftFSB to bump it to 1007mhz when need to run benchmarks. The vid card is held at 135/185 until I am actually playing games or benchmarking. I use GeforceTweak to quickly overclock).

The gains for overclocking the core are small but measurable. I think my 3DMark 2000 score increased about 100 pts going from 120mhz to 150mhz. However, I gained 500 pts increasing my memory from 166 to 210mhz. My best score is 5640ish for the default benchmark. I only get 2323 for 3DMark 2001 which doesn't look too good. New games may be a problem.