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Mixing Graphics Cards?

samurlesamurle Posts: 94
in Daz Studio Discussion

Hello!
I'm thinking about getting a new graphics card, a GTX 1070 or 1080, to replace my old GTX 660 card.

At first, I thought I would just replace it, as I only have one card.  But, then I realized, why discard the old one, when I can have both cards installed.  But, obviously, they won't be the same card.

My question is:
- Both cards are GTX cards, both are CUDA capable.  Will I see any improvement in rendering speed if I install both cards?
- Will Daz Studio recognize and use both cards as CUDA devices, regardless if the cards are in SLI mode or not?
  I'm not sure if I can even use SLI with these two cards.

Any thoughts on this?

Comments

  • Richard HaseltineRichard Haseltine Posts: 102,464

    Iray doesn't use SLI - it should be disabled for DS even if it is set up on the system. If Iray can use your current card it will be able to use it still, alongside the new one (though remember that as yet the 10x0 cards are suported only in the Public Btea version of DS - and that has issues with some older CPUs) but I'm not sure how much good the older card would do.

  • nickalamannickalaman Posts: 196

    SLI only works with the same cards, but is not required for iray. As far as having 2 cards in the system, yes they will work together to speed up rendering, but as of cuda 7.5 all cards slow down to the speed of the slowest card. So in your case the GTX 1070 will drop it's speed from 1450mghz to match the speed of the GTX 660 CARD, which is probably around 900mghz. This might have been corrected in the latest version of cuda. 

  • samurlesamurle Posts: 94
    edited November 2016

    Ah, I didn't realize a single slow GPU would affect the entire system in parallel processing.  I assumed parallel processing was designed to remove such bottlenecks.  Each GPU gets a slice of the CPU's time, or something like that.

    And I did download the beta build recently, thanks for that.

    Post edited by samurle on
  • L'AdairL'Adair Posts: 9,479
    edited November 2016

    What about using an older nvidia card that doesn't have any cuda cores? I have an NVIDIA GeForce GTS 250 in the seven year old computer I just retired. My newest computer does not have on-board video, just the GTX 1080, so I'm wondering if I could install the GTS 250 and set the computer to use it for the display. This computer has Win10Pro installed, but I keep it offline.

    Any thoughts or suggestions?

    ETA: Never mind. Found this on the Geforce forums:

    "Support for Geforce 300 and older has stopped. You will require a new video card to use both video cards AND the newest video drivers." (link)

    crying

    Post edited by L'Adair on
  • samurlesamurle Posts: 94
    edited November 2016

    That sounds like a good idea.  I could configure the 2nd card as a dedicated rendering device for CUDA, and hook the old card up to my monitor for display purposes.  I think that would free up VRAM, but, would that free up the CPU much?  Things slow down a lot when Daz Studio is rendering.

    You know, I think I could speed up my computer by unchecking the "CPU" option, and just use the GPU for rendering.  I just realized I had both options checked.

    Post edited by samurle on
  • L'AdairL'Adair Posts: 9,479
    samurle said:

    You know, I think I could speed up my computer by unchecking the "CPU" option, and just use the GPU for rendering.  I just realized I had both options checked.

    Test it. I took an old scene I'd done maybe a year earlier and render it with various options. It turned out leaving CPU checked on my system was faster, but Optix checked slowed things down. That's with an i7-6900, (8-cores,) and one GTX 1080. When I get a second GTX 1080, I'll test it again...

  • namffuaknamffuak Posts: 4,176
    samurle said:

    That sounds like a good idea.  I could configure the 2nd card as a dedicated rendering device for CUDA, and hook the old card up to my monitor for display purposes.  I think that would free up VRAM, but, would that free up the CPU much?  Things slow down a lot when Daz Studio is rendering.

    You know, I think I could speed up my computer by unchecking the "CPU" option, and just use the GPU for rendering.  I just realized I had both options checked.

    And then there are the times when the cpu does help, but it isn't really worth it. I've a scene that takes 52 minutes to render with cpu and my 980 ti; it takes 57 minutes with the 980 ti alone. I ask myself - is it really worth running a 3.5 GHz 6-core I7 at 100% for 52 minutes just to knock 5 minutes off the total time? And I've decided it is not. According to the log (going from memory here) the 980 ti did 6,000+ iterations and the cpu did less than 500 in that 52 minutes.

  • samurlesamurle Posts: 94

    Sorry, what I mean by faster is that my computer would be more responsive while Daz Studio is rendering in the background.  If I left the CPU option unchecked, I could do other things while I wait.

     

  • areg5areg5 Posts: 617

    I run 2 different cards.  You'll see faster times using both of your cards as long as the scene size doesn't exceed the capacity of the older card.  If the scene is too large, the rendering will default to the card with the bigger memory.  To the best of my knowledge, Cuda is Cuda and the results should be additive.

  • samurlesamurle Posts: 94

    Sure, I expect to increase my CUDA cores to 2560 + 960 = 3520 with my old card.  Even though its clock speed is slower, I think the benefit of more cores would outweight the costs.

  • areg5areg5 Posts: 617

    Yeah.  I think the clock speed isn't really much of an issue.  The issue is the older card probably only has like 2 gig of Ram, right?  So it will only be useful on smaller scenes.

  • Silver DolphinSilver Dolphin Posts: 1,617

    Having both cards in your system means that you can dedicate the new card to Iray renders only and use the older card to run your monitors.

  • jurajura Posts: 50
    samurle said:

    Hello!
    I'm thinking about getting a new graphics card, a GTX 1070 or 1080, to replace my old GTX 660 card.

    At first, I thought I would just replace it, as I only have one card.  But, then I realized, why discard the old one, when I can have both cards installed.  But, obviously, they won't be the same card.

    My question is:
    - Both cards are GTX cards, both are CUDA capable.  Will I see any improvement in rendering speed if I install both cards?
    - Will Daz Studio recognize and use both cards as CUDA devices, regardless if the cards are in SLI mode or not?
      I'm not sure if I can even use SLI with these two cards.

    Any thoughts on this?

    Hi there

    I'm running Zotac GTX 1080 AMP! with EVGA Titan X SC with Rajintek Morpheus VGA cooler and no issues at all,although only in latest DS build we can render with "Pascal" GPU and still performance is not the best,difference between the Titan X and Pascal GTX1080 is not so big and in many my tests Titan X is actually faster 

    Yes you should see improvement in rendering although you will be limited by VRAM on GTX660,you can use GTX660 for powering the displays or use that card for rendering,I've done that with Titan X and GTX780 and yes DS should recognize both cards,in Nvidia Control panel you just need to check if yours cards are set to CUDA All

    SLI is not or shouldn't be used in rendering or when you render and you can't combine two different cards for SLI,you need to have same GPU,only thing which you can do is use GTX660 as PhysX

    Hope this helps 

    Thanks,Jura

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