Unlocking the GeForce 6800

Washoe

Senior member
Nov 13, 2003
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Unlocking the GeForce 6800

combine this with 2Xtreme21's great How to unlock Pipelines and Vertex Shader on a 6800nu thread of course!

Thought my fellow 6800nu owners would be interested! It's an excellent read and step-by-step instructional using RivaTuner 15.5.

with benchmark comparisons too!

As you?ve just seen, NVIDIA?s GeForce 6800 can be easily modified from a 12-pixel pipeline/5 vertex unit mainstream card into a 16-pipe contender with just a few simple clicks of the mouse.

As you?d expect, turning on all of the NV40?s pixel/vertex pipelines brought an immediate performance improvement in all applications we tested. Of course, the performance increase varied depending on the application tested. In Chronicles of Riddick, we saw an improvement of anywhere from 5-8%, with the result varying depending on screen resolution. Far Cry saw even greater benefits, with the 16-pixel/6 vertex unit GeForce 6800 configuration outperforming the 12-pixel/5 vertex GeForce 6800 by 7-10% in the volcano level, with performance in the training map varying between 5-10%. DOOM 3 and Half-Life 2 also saw some pretty good performance gains. Pacific Fighters was really the only title that didn?t benefit from the extra pipelines. Sure, the numbers were a little higher, but well within the margin of error.

...all of our attempts to overclock three different GeForce 6800 vanilla cards were unsuccessful. We were able to easily unlock the pipes on all three cards, but with each of them we could never overclock the graphics core or memory, not even 5MHz. Whether we used RivaTuner to OC the boards or the NVIDIA control panel, each time we tested our settings the GeForce 6800 card would fail to pass the overclocking test. Even if we were able to hit the speeds we achieved in our EVGA e-GeForce 6800 review (400MHz core/810MHz memory), it still wouldn?t have been enough to catch up to say, a GeForce 6800 GT. The GeForce 6800, even with all 16 pixel pipes and 6 vertex pipes running, still gives up too much memory bandwidth to the GeForce 6800 GT to be a 6800 GT killer. The 6800 board?s 128MB frame buffer would also be a huge impediment to catching up to a GT.
 

ddogg

Golden Member
May 4, 2005
1,864
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good thread....should stop the repeated threads being posted on how to unlock the remaining pipes
 

2Xtreme21

Diamond Member
Jun 13, 2004
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Yeah those benchmarks are uber. I wish I had the time / resources to conduct those tests. Also, great guide.
 

Plester

Diamond Member
Nov 12, 1999
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surprised at firingsquad - they fell victim to a rookie mistake - not being able to overclock the cards once unlocked.

under the power user tab in rivatuner, selecting NVIDIA\Overclocking, and setting DisableInternalClockTest to 1 solves the problem.

very common problem, very simple solution. i couldn't overclock my vanilla 6800 1mhz either without doing this. after the power user switch, card flies artifact free at 390/910 (def. volts) and 425/950 (2.85v vmemm and 1.3v vcore) stability confirmed w/ extensive testing using 3dmark05, riddick, doom3, rthdribl, etc.

The switch in rivatuner

The results using Riddick
 

Mingon

Diamond Member
Apr 2, 2000
3,012
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The vcore of a 6800 is only 1.1v (1.0v for 6800le) by flashing the card and changing it to 1.3v you will find that you can overclock easily.
 

Plester

Diamond Member
Nov 12, 1999
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actually the LE is 1.1v, the vanilla 6800 1.2v, the GT 1.3v and the Ultra 1.4v. As I mentioned I could hit 390/910 at default voltage not 1.3v.
 

richardrds

Senior member
Dec 7, 2004
303
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I have used Riva Tuner to modify my BFG6800OC to 16p/6vs, and i can Overclock the card with the test on to around 395/760.

I will try to turn the test off and see if i can push it furthur, but i am also interested on what you are flashing that gives you access to adjust the vcore voltage and vdimm voltage on the 6800nu's, i have not seen any info on this anywhere. Could you point me to a thread that discusses this, or let me know what you are flashing (i assume the code on the 6800 itself) and what the new flash file is called.
 

Plester

Diamond Member
Nov 12, 1999
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disabling the internal test probably won't help your overclock. you are doing well on the core, not so great on the ram. see the links below if you want to start an unhealthy obsession that may bring you a much higher overclock and/or a burnt up card.

disclaimer - i bought my card used fairly cheap because the previous owner had busted one of the big capacitors off the card, so with any warranty service out of the question i feel no fear modding this card to to the hilt. also it is water cooled.

nV News Forum has plenty of info on bios flashing, search on posts by jimmor.

xtreme systems forum for all the vmemm info - need to solder variable resistors to be able to adjust vmemm tho.

Also the fact that many unlockable cards cannot overclock at all (without disabling the internal test) may very well be small imperfections in the unlocked areas, but again i and many others have spent way too much time stress testing and looking for artifacts and never seen them, unless like any overclock, the card is pushed too far.
 

Navid

Diamond Member
Jul 26, 2004
5,053
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Originally posted by: Plester

very common problem, very simple solution. i couldn't overclock my vanilla 6800 1mhz either without doing this. after the power user switch, card flies artifact free at 390/910 (def. volts) and 425/950 (2.85v vmemm and 1.3v vcore) stability confirmed w/ extensive testing using 3dmark05, riddick, doom3, rthdribl, etc.

The switch in rivatuner

The results using Riddick

What does the "EnablePerfLevelForcing" switch do?
 

Plester

Diamond Member
Nov 12, 1999
3,165
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What does the "EnablePerfLevelForcing" switch do?

i think that gives you the drop down box under core and clock sliders on the rivatuner overclocking page labeled 'force performance level'.