NVLink between different GPU models?

[JFichtmueller]

Hi,
I'm super excited about the new GPU generation having NVLink support.
But so far I've only found benchmarks and tests with NVLink on identical cards.
I wonder, is it possible to get NVLink to work with different GPU models?
Can you combine the memory of a 2080 ti with the memory of a non ti to get 19GB?
Or will 2 RTX 2080 from different GPU vendors stack their memory?
Thanks!

[savage309]

We have tested mixing different vendors and it works fine.
We have not tested NVLINK in mixed 2080 with 2080ti setups.

Best,
Blago.

[MANUEL_MOUSIOL]

Sorry for hijacking this thread, but the title just fits, so vital Information will be in one place.

I'm planning to build a pc with four 2080tis, using nvlink to double memory. The vendor told me that it's not possible to use nvlink with four cards (connecting two and two together) . That doesn't make any sense to me, so I would like confirmation from Chaosgroup before my purchase. Thank you

[vlado]

So there's some bad news here unfortunately :/ In our initial testing with the 416 drivers, it worked fine with four cards in a 2x2 configuration. However it turned out this may not have been NVidia's actual intention. Two cards will work fine, but as far as I know support for four cards will likely go away. <insert rant here>

Best regards,
Vlado

[MANUEL_MOUSIOL]

Wow . This is more then disappointing . No scalability!
is this different for the titan or quadro btw?

[vlado]

is this different for the titan or quadro btw?

This limitation will definitely not be there for Quadros; they can be linked in any way. I'm not sure about the Titan, but I would assume it would be the same as GeForce.

Best regards,
Vlado

[MANUEL_MOUSIOL]

Ok. Thank you .I'm not sure how to handle it from here . If I want to scale my rendering speed AND vram.. There is only distributed rendering left I guess... But makes things even slower...
the 1080tis are not sli supported, right?

[super gnu]

seems to me a copy of the 416 drivers might be worth keeping

[MANUEL_MOUSIOL]

Not a bad idea, but I'm not sure if it's a good idea to base my business performance on old drivers for the next years...

[squintnic]

Sorry for hijacking this thread, but the title just fits, so vital Information will be in one place.

I'm planning to build a pc with four 2080tis, using nvlink to double memory. The vendor told me that it's not possible to use nvlink with four cards (connecting two and two together) . That doesn't make any sense to me, so I would like confirmation from Chaosgroup before my purchase. Thank you

I don't see how you would connect 2 x cards and then connect those 2 x cards on top? Were you expecting to be able to get to 44gb of VRAM available with the 2080Ti ?

Disappointing to hear about the lack of support here, I have just got a 2 cards with an nvlink and was planning on getting another 2 x cards with nvlink in a couple months....but had been expecting 22gb vram but over the 2 x 2 setup.

Confusing

[MANUEL_MOUSIOL]

That's what I was expecting. 4 cards, 22gb ram in total.

I have to learn to use octane for a job and noticed that it features something called out of core ram usage where system is being used instead of vram . Obviously things get slower but it still is better than my being able to render. I have no experience with it at all, or octane yet ....
has Chaos planned to implement something like that?

[Nejc Kilar]

So there's some bad news here unfortunately :/ In our initial testing with the 416 drivers, it worked fine with four cards in a 2x2 configuration. However it turned out this may not have been NVidia's actual intention. Two cards will work fine, but as far as I know support for four cards will likely go away. <insert rant here>

Best regards,
Vlado

Does anyone know if this is still the case?

[Micha]

I have two 2080ti and one 1080ti at my PC. I like to use the 22GB of the 2080ti per NVlink for complex projects and for smaller project I want to use all three cards at 11GB. Is it a problem for the NVlink if a 1080ti is in the PC? Will it kill the 22GB, also if I don't use the 1080ti for rendering (disabled at V-Ray options only)?

[MANUEL_MOUSIOL]

I tested it once and it rendered fine with two 2080tis and nvlink and the 1080ti unchecked.

I did have a problem though with capture one not being able to start with the nvlink enabled. And once Photoshop acted weird.
I hate that it takes so long to disable nvlink and I have to force close so many programs to do it.

[Micha]

MANUEL_MOUSIOL Thank you, so I should get it working. At the moment I have the impression in NVlink mode I can't not use more VRAM than without NVlink. If you like you could read here, maybe you have an idea what could be wrong or how to test the 22GB VRAM usage, at the time at approx. 11GB it crashs.
https://forums.chaosgroup.com/forum/...e-frame-buffer