RTX4090 *and* RTX3090 in one PC

feldarzt

Hey guys!

I kinda expect the answer to be something like "No, dumbass, you can't!" but still...

So the 4090 is released and being sold. Long story short, I want it and planning on buying it. However, I have a more or less fresh 3090, which I can't blame for anything. So, could I use both cards in DAZ Studio simultaneously? Like for rendering?

hansolocambo

I'd sell the 3090 and keep the 4090. In a computer slower things don't adapt to faster ones. It's the opposite. So you're probably going to end up with more VRAM for textures, but also with an expensive 4090 that runs at the speed of a 3090.

A single RTX 4090 beats 2xRTX 3090 in SLI. But an RTX 3090+4090 combo ? I doubt it's a sound idea. Better sell one and save to buy a 2nd RTX 4090 later.

felis

I wouldn't rush to buy a 4090. Better wait till Iray in Daz Studio has been updated to support it, and there is released a Studio driver supporting 4090.

Or maybe wait till Daz has fixed the forums, but then it would probably a 6090 you would upgrade to.

feldarzt

That's a reasonable thought, indeed. However, there is news about American top managers of electronics-producing companies in China resigning and moving out of the country en masse. Something about the new decree from the POTUS about restrictions for non-US-based producers of microchips. So I imagine that a delay or even stop of GPU production is to be expected. Ergo, gotta get it while it's available.

felis said:

I wouldn't rush to buy a 4090. Better wait till Iray in Daz Studio has been updated to support it, and there is released a Studio driver supporting 4090.

Or maybe wait till Daz has fixed the forums, but then it would probably a 6090 you would upgrade to.

PerttiA

The first versions of any hardware products often have teething problems, which will later be fixed making physical changes, changes that can't be made with firmware of driver updates.

Leana

hansolocambo said:

No. Sell one keep the other. 

I've not read anything about incompatibility preventing one to have both cards in one system (providing your motherboard supports it and your power supply is big enough).
In that case, DS could indeed use both cards to render, as long as your scene fits in the VRAM of each of the cards.

Jeremion

Hello, I have both in my computer, it works fine. I need to upgrade my power supply. The only issue is coming from dForce (current bug on the lastest drivers)

LegacyAF

I run 2 980s and a 2080 Super with no issues. Daz handles and uses them fine.

feldarzt

Well, yes. And it probably would be reasonable to wait a year or so. But you know that itch of DO WANT that happens to people sometimes :) And I've simply fallen for those Nvidia's marketing and various reviews.

PerttiA said:

The first versions of any hardware products often have teething problems, which will later be fixed making physical changes, changes that can't be made with firmware of driver updates.

feldarzt

Well, the PSU will be replaced with a 1600W one, so I'm pretty sure it'll be enough. 

About scenes fitting the VRAM. So it would be impossible to share both cards VRAM? Only their computing power?

Leana said:

hansolocambo said:

No. Sell one keep the other. 

I've not read anything about incompatibility preventing one to have both cards in one system (providing your motherboard supports it and your power supply is big enough).
In that case, DS could indeed use both cards to render, as long as your scene fits in the VRAM of each of the cards.

feldarzt

 Cool! Thanks for sharing your experience "from the field"!

Jeremion said:

Hello, I have both in my computer, it works fine. I need to upgrade my power supply. The only issue is coming from dForce (current bug on the lastest drivers)

Leana

feldarzt said:

Well, the PSU will be replaced with a 1600W one, so I'm pretty sure it'll be enough. 

About scenes fitting the VRAM. So it would be impossible to share both cards VRAM? Only their computing power?

Indeed, VRAM won't be shared, but it will use the CUDA cores from both cards for computing. 
It is possible to have 2 GPU pool their VRAM for Iray rendering (with limitations) using nvlink, but last I checked nvlink needs the two cards to be the same and isn't supported by 4090 anyway. 

feldarzt

 Well, I guess I'll have to be reasonable and try to fit all my scenes into the VRAM of a single card.
And yeah, that's an unfortunate decision by Nvidia to cut nvlink support from the 4090. Though, I think they will eventually release an updated version of it with nvlink support. Tech reviews mention space for nvlink pin array on some 4090s, so I guess it was initially planned to be supported but somehow was cut later. Oh well, time will tell.
Anyway, thanks for the info!

PS
Love your profile pic :)

Leana said:

feldarzt said:

Well, the PSU will be replaced with a 1600W one, so I'm pretty sure it'll be enough. 

About scenes fitting the VRAM. So it would be impossible to share both cards VRAM? Only their computing power?

Indeed, VRAM won't be shared, but it will use the CUDA cores from both cards for computing. 
It is possible to have 2 GPU pool their VRAM for Iray rendering (with limitations) using nvlink, but last I checked nvlink needs the two cards to be the same and isn't supported by 4090 anyway. 

villko05

Keep 3090, selling it does not make any sense. And no. 4090 won't be slower just because your second GPU is 3090. The only reason 4090 would perform slower than it should is because of Daz3D software itself.

You probably can wait for 4090, because how I read it is that daz3d currently does not support the new raytracing Nvidia version so it can't fully utilize 4090 performance.

Both 4090 and 3090 are 24gb vram, your daz software will have 24gb vram total (minus windows and other software that uses vram).