NVIDIA GeForce 7900 GTX Lockups

[Pinnacle]

http://www.pcper.com/article.php?aid=235

[gr8golf]

Dammit - that explains my *freezes* in games and the eventual return of the game. This basically tells me that I won't be able to overclock my GTX. Wish I had known this prior to purchase - I'd have bought a 7900 GT and expected to overclock it some.

[WeStSiDePLaYa]

i had same issue when i pushed old 5950U too far.

[Reznik Akime]

Indeed, I had a 5600 that would do the same when the core was past what it liked. Althought it would usually be about ten seconds or so.

[freecableguy]

more cowbell (i.e. volts) fixes the problem

[Flak Monkey]

I have the same problem with my 5900xt but I've been told that it's because the core is starved for voltage and not that it doesnt have the capability to run that speed.

[ahmad]

So all those models: xXx, XXX, KO, CO, Superclocked, OC won't exist anymore..

Seems like stretching it to compete is not a healthy solution. And these are with mild clock increases as well..

[Starscream]

So all those models: xXx, XXX, KO, CO, Superclocked, OC won't exist anymore..

Seems like stretching it to compete is not a healthy solution. And these are with mild clock increases as well..

they are stil selling em so i guess this isnt a big problem.

ive seen topics on forums were people had a pre-overclocked 7800/7900 from XFX/eVGA wich wouldnt run the the core clock it should run with or had problems (lock ups).
these people contacted eVGA/XFX and send the card back for RMA or were send a new bios to fix the problem.

so eVGA and XFX know of this problem for a good while now and seeing the fact that eVGA/XFX stil sell their pre-overclocked cards i think that they see no real problem and that the people that have problems with their pre-overclocked cards are only a small percentage of all the buyers and that selling these cards is stil profitable for them 2 companys.

[freecableguy]

or were send a new bios to fix the problem.

I personally think the lockups are related to memory. The updated BIOS was most likely relaxed timings and/or memory speeds. We need to get a new version of the NiBiTor BIOS editor so that we can examine the timings ourself. I have a good feeling they are quite a bit tighter on the 7900 series than the 7800 series...

-FCG

[Starscream]

I personally think the lockups are related to memory. The updated BIOS was most likely relaxed timings and/or memory speeds. We need to get a new version of the NiBiTor BIOS editor so that we can examine the timings ourself. I have a good feeling they are quite a bit tighter on the 7900 series than the 7800 series...

-FCG

true cause benchmarks benefiting from tight timings seem to score very wel with 7900 cards.

something that also says that this lockup problem is only minor is due to the amount of people overclocking their 7800/7900 and dont have a problem.
i think its a small percentage of the people that got it.

if it does it at guaranteed speeds contact the manufacturer and RMA it.

[Cooper]

With 7600GT lockups are related to delta. Geometry processing unit should be downclocked to have succesfull OC. Maybe with 7900 series cards it`s just the same ?

[Raphie]

I have the XFX 7900 GTX 512 (PV-T71F-YDPR) 690-1750 and it works perfectly fine both 3Dmark05, 06 and BF2 no delays whatsoever.

However: I've noticed that Coolbits auto settings comes up with the same values as the default values, manually i can get the card to 710/1890 in coolbits , but that doesn't seem to add very much to the overall score (some 06 values go up, while others go down) With Powerstrip i'd put the settings on 728/1950. i then get mild artifacting and again the overall score does not increase significantly. there seems to be some choking going on at those clocks, however, that wasn't vissible while watching the 06 benchmark.

Overall i am very happy with my card and either mine does not suffer from the issue, or i don't consider it an issue

[gr8golf]

How much did you drop on that thing and where did you buy it Raphie?

[freecableguy]

How much did you drop on that thing and where did you buy it Raphie?

I got a pair from ZZF. Just need to be quick and make the purchase when they show up. When they do appear they are gone fast. Although, it has been over 2 weeks since i saw them anywhere last.

-FCG

[k|ngp|n]

Based on my testing, this behaviour only occurs WHEN OVERCLOCKING THE CARD PAST 700 MHZ ON THE CORE COUPLED WITH THE PCI-EX FREQ. NOT MATHCED PROPERLY WITH CORE SPEED. With the 50mhz delta on some or all of these cards, it's so easy to see how this can happen lol.
Such a simple fix too it.
I have put my cards through more testing and stress than anyone who has used these no doubt, and the ONLY time this freezing has ever occured is when the pci-ex freq is out of sync with core speed. It's the way the cards are designed. I am not 100% thrilled about it, but there is a workaround.
750+ on air is rock stable and never had a freeze, unless pci-ex freq. wasnt matched to core speed.

[freecableguy]

Based on my testing, this behaviour only occurs WHEN OVERCLOCKING THE CARD PAST 700 MHZ ON THE CORE COUPLED WITH THE PCI-EX FREQ. NOT MATHCED PROPERLY WITH CORE SPEED. With the 50mhz delta on some or all of these cards, it's so easy to see how this can happen lol.
Such a simple fix too it.
I have put my cards through more testing and stress than anyone who has used these no doubt, and the ONLY time this freezing has ever occured is when the pci-ex freq is out of sync with core speed. It's the way the cards are designed. I am not 100% thrilled about it, but there is a workaround.
750+ on air is rock stable and never had a freeze, unless pci-ex freq. wasnt matched to core speed.

For 820Mhz on the core I am using a PCI-e speed of 122Mhz. Is this right? I really have no idea. Is it safe to say that PCI-e must be increased with core speed? What are the trip-points? Min and maxes? Acceptable ranges all the way up to 900Mhz core? Great topic and post kingpin....but we need more detail from what you have learned. Please share. Thanks.

-FCG

[zakelwe]

Freeze- release has been a feature on nvidia cards since the FX range so it is funny that it suddenly becomes an issue now. Maybe it is the clock delta + not putting up the PCie speed as mentioned above that is making it more prevalent ?

Some sites don't bench enough to be able to work it out, rather than do a lot of permutations they just bang off an email .... that is not the XS way though

Regards

Andy

[Raphie]

How much did you drop on that thing and where did you buy it Raphie?

599 euro which is roughly 725,00 USD (everything is 20% more expensive in europe)

[k|ngp|n]

Is it safe to say that PCI-e must be increased with core speed?
-FCG

Absolutely fcg. There is a DIRECT relationship between the two. Both must be scaled together for the card to function properly at higher core clocks greater than 720mhz. Doesn't matter what mobo, as the card behaves the same on p4gd1 and DFI as well as others mobo's(i have heard from friends).
Best way to find the sweet spot is to just test for yourself, because it really depends on your particular card(s) core limit.
IN SLI we are limited to around 122-124mhz no matter what as it is either a limitation of the DFI(chipset), so there is a defintive wall there with the cards at approx 930-940mhz(this is real clock no delta). I would love to chat with Oskar about this BTW.
Best way to test this is with single card only. Most cards I think can do close to 750mhz out of the box, but I see lots of guys saying there at 720. Greater than 720mhz needs 118mhz+ on pci-ex. Thats a good place to start, then just keep scaling both up together till you hit your cards limit at whatever votls/cooling you are running.
The symptoms of the "pcie-x bug" are maybe gt1 will pass, but after the loading screen of gt2 or gt3 the thing just stalls and doesn't do anything for a brief moment, then suddenly restarts. When you get the score, it's usually majorly bugged low in that test or all the tests when this happens. You will need either to raise or lower the pci-ex freq when this occurs to find that right spot to get it stable.

[wkmgt]

Thanks for the info Kingpin......

[gr8golf]

What if you are on stock cooling and just trying to run 690 or so? Recommended PCI-e freq?

[k|ngp|n]

What if you are on stock cooling and just trying to run 690 or so? Recommended PCI-e freq?

I was able to run my cards np below 700mhz with 100mhz pci-ex and didnt have any issues. The need for pci-ex scaling linearly with core clocks doesnt seem to kick in until you get over 700mhz.
Also keep in mind that if you have the pci-ex frequency set too high for the given core clocks, you get the same problems that you would if the pci-ex freq was set to low for the given core clocks.

[cantankerous]

Wow, this is weird HAVING to raise PCI-E bus speeds just to overclock your card. I take it this is only with Nvidia cards? I have never had to do this with my X1900XTX.

I am unsure but 120+mhz on the PCI-E bus won't be damaging to ANYTHING in the long run?

[Raphie]

Kingpin,

Can you give us some ratios which worked for you?

i.e. 700 core / 103 PCIe
710 core / 108 PCIe

etc....

This would give us an idea where to start.

ThnX

Raphie

[Nilson]

yesterday I post it on russian overclockers.ru site:
http://www.xtremesystems.org/forums/...37#post1395037
just some additional info. I will add it to our 7900GT/GTX FAQ.

Guys... I can't found FAQ about 7900GT/GTX on your site

I can translate my FAQ (warning: russian language ) with fotos. The main info was taken from xtreme threads even you can find your fotos there :thumbsup:. Or I can help you guys to create your own FAQ(I have experience in analyze posts in xtreme threads and our G71 threads)