Folding in SLi

_k_k P-Town, Texas
edited October 2009 in Folding@Home
NVidia fans rejoice! With the release of driver 190.38 it is already being reported that folding is capable while SLi mode is enabled on 2, 3, and 4 way SLi. In the folding forums it was reported as a failure but digging into the Evga forums there are mutiple people with multiple set-ups that are acomplishing this. Currently from what I have read there are 24 hour no error runs and shorter, nothing long term has been posted. There are mixed reports listed in the evga thread of small ppd decreases and no decrease.

Now only if extended desktop would work with SLi on xp.

Comments

  • lordbeanlordbean Ontario, Canada
    edited July 2009
    I tried to fold on both my nvidia GPUs simultaneously (although not SLi)... the program says it doesn't recognize the 9600 GT as a card it can use. Maybe it's not CUDA-enabled.
  • _k_k P-Town, Texas
    edited July 2009
    Are you sure you have your desktop extended to that video card? Did you set the arguments in your launch icons for GPU2 to different GPUs and different Machin IDs?
  • lordbeanlordbean Ontario, Canada
    edited July 2009
    Yes, yes (although I didn't use the -forcegpu flag), yes I set the apps with two different machine IDs.

    Do I need to use the forcegpu flag? I didn't think it applied in this situation.
  • _k_k P-Town, Texas
    edited July 2009
    You should not have to but it won't hurt to try at this point, if you have two different cards installed it might actually be causing the conflict. Also, I assume you already double checked your target links in your launch icons. I would screw around with the 9600 while the other client is turned off.
  • lordbeanlordbean Ontario, Canada
    edited July 2009
    The links do definitely go to two separate installations, yes. I've read in some other places that depending on certain factors in the system, the 9600 GT isn't always recognized as a usable card... I'll just have to mess with it and see what I can come up with. I have my GTX 285 folding at least, that's the brunt of my graphics hardware.
  • lordbeanlordbean Ontario, Canada
    edited July 2009
    Bah, I just can't get it to recognize the 9600 GT. Maybe it has issues running on more than one kind of GPU simultaneously (GTX 285 and 9600 GT being a generation apart).

    Oh well.
  • mew905mew905 Saskatchewan
    edited July 2009
    I wouldnt try it with both of them, for some reason F@H GPU hates seeing two different shader counts, and will drop the 285's PPD dramatically.

    HOWEVER Does this mean that both cards will fold as one, doubling PPD on said card? (I dont expect it to score higher than two non-SLi'd cards though)
  • lordbeanlordbean Ontario, Canada
    edited July 2009
    That option actually isn't technically available, since to my understanding you have to SLi two or more of the same GPU... I can only pair my GTX 285 with another GTX 285 to link them together.

    Even with ATI, two cards that are a generation apart can't be crossfired. If 9600 GT and GTX 285 were built by ATI I still couldn't do it.
  • edited July 2009
    I believe you are correct lordbean. From what I've read, they have to be the same core. If I understand what I've read correctly, two different GTX 2xx cards could be put in SLi, but a GTX 200 series and a 9000 series cannot. I believe GTX 200 series and GTS 200 series can't even SLi together but I'm not sure on that.
  • _k_k P-Town, Texas
    edited July 2009
    Thats correct, according to NVidia. The only difference that is allowed is clock speeds or memory amounts, a series difference or model difference does not allow SLi to be used.
  • lordbeanlordbean Ontario, Canada
    edited August 2009
    I resolved why I couldn't do this, for anyone interested... I made a discovery on the nvidia section of stanford's folding forums that in order for two separate cards to be folding, they MUST have the same number of shader cores, else it will not work. In other words, my 285 can be paired with a GTX 275, 280, 285, or 295, but anything else will not work (at least, I believe that was the list. It was something like that anyway).

    I could fold on the 9600 GT, but it would have to be used as the primary monitor in the system, meaning most 3D apps would also try to use it and ignore the GTX285.
  • _k_k P-Town, Texas
    edited September 2009
    I am doing this now! I figured out what the real issue was when I turned on SLi in Win7, second monitor was connected to the second video card. You have to move cables before enabling SLi otherwise it screws everything ups and will BSOD. Currently, it looks like SMP and both GPU clients are taking small hits in ppd. Also there is some stuttering and small stops in the graphical parts of the OS. I consider this worth it to be able to still fold on two cards while having two monitors in SLi.....gaming is so much better FPS wise with dual 88GTs'
  • mew905mew905 Saskatchewan
    edited September 2009
    lordbean wrote:
    I resolved why I couldn't do this, for anyone interested... I made a discovery on the nvidia section of stanford's folding forums that in order for two separate cards to be folding, they MUST have the same number of shader cores, else it will not work. In other words, my 285 can be paired with a GTX 275, 280, 285, or 295, but anything else will not work (at least, I believe that was the list. It was something like that anyway).

    I could fold on the 9600 GT, but it would have to be used as the primary monitor in the system, meaning most 3D apps would also try to use it and ignore the GTX285.

    It will work, people over at www.xcpus.com have done it, however it slows down the faster one significantly.
  • LeonardoLeonardo Wake up and smell the glaciers Eagle River, Alaska
    edited October 2009
    So, what's the latest on this? Two GPUs processing a single project in SLI (in tandem) will produce the same, more, or less than the two GPUs processing units independently?
  • mew905mew905 Saskatchewan
    edited October 2009
    Leonardo wrote:
    So, what's the latest on this? Two GPUs processing a single project in SLI (in tandem) will produce the same, more, or less than the two GPUs processing units independently?

    No, the most you can do with nVidia GPU's is fold two WU's at once, the new Radeon 5k series can do it in tandem (they both work on the same unit at the same time, doubling speeds, they can do the same with games (obviously), video conversion, etc. All because Crossfire is done via a chip physically on the card. Rather than seeing 70% gains from SLI/CF, the 5k you will now see closer to 90 to 95% gains. ATi did a great job with this one. GPU3 is coming out in a few months too which will boost ATi's performance. :rockon:
  • LeonardoLeonardo Wake up and smell the glaciers Eagle River, Alaska
    edited October 2009
    Thanks for the info.
    the most you can do with nVidia GPU's is fold two WU's at once
    Trust me, I'm all over that! ;)
    GPU3 is coming out in a few months too which will boost ATi's performance.
    Bout time. It will allow ATI fans to excel in games and in Folding.
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