Upgrading PC: Motherboard for 2x3080 GPUs?

[Peter Sunna]

Hello all,

First time poster here. I'm looking to upgrade my workstation once the new GPUs are easier to come by.

I would like 2 new GPUs, either 3080 or 3090 and wondering what motherboard I would need to get if I want to keep my CPU (AMD Ryzen 9 3950X AM4, 3.50GHz, 16-Core)? I've been researching but unable to figure this out on my own. Also, I'd like to keep my RAM but open to upgrade if performance is significantly improved (Corsair Vengeance LPX Black 64GB (4x, 16GB, DDR4-3200, DIMM288))

Thanks in advance!

 

[Jake]

SLI is only compatible with the RTX 3090. The others NVIDIA will not be supporting. I am unsure in which Motherboard sorry.

 

[Tived]

Hi Peter,

You will run out of PCIe lanes if you have any other cards installed in the motherboard, but you could possible run them both in x8 mode!

what motherboard do you currently have?

Henrik

 

[Peter]

Hi Peter,

You will run out of PCIe lanes if you have any other cards installed in the motherboard, but you could possible run them both in x8 mode!

what motherboard do you currently have?

Henrik

Hi Henrik,
Thanks for the reply. I have an ASUS Rog Strix X470-F Gaming board right now. I think it can handle one RTX 3080 but want to run a dual setup for my next build.

 

[Tived]

Hi Peter,

well it says you can run SLI 2-way, but it will be at x8 speed as predicted, there is spacing enough for most cards, given they take up more and more space these days.

i'd say you are good to go, no need to upgrade the motherboard, now you will need to look at your power-supply to see if it will pull two of those beasts ;-)

will be awesome!

all the best from Down Under

PS: You may want to check if the 3080 will run SLI! as per Jake's message!

see this https://www.pcworld.com/article/357...n-slis-coffin-no-new-profiles-after-2020.html

RIP: Nvidia slams the final nail in SLI's coffin, no new profiles after 2020

A glaring fact jumped out at me while I was sifting through Nvidia’s product pages for our GeForce RTX 30-series vs. RTX 20-series spec comparison: Only the monstrous $1,500 GeForce RTX 3090 includes support for NVLink, the proprietary connector that enables SLI mult-GPU configurations. Even the $800 GeForce RTX 3080 lacks it, and Nvidia calls that graphics card the 30-series flagship. (The RTX 3090 is a “BFGPU” above and beyond the rest.) Given that Nvidia controls 80 percent of the graphics card market, it seems clear that the days of slapping multiple graphics cards into your PC to boost frame rates is effectively over.

I think you better get the big checkbook out and go for the 3090!

 

[Peter]

View attachment 40

Hi Peter,

well it says you can run SLI 2-way, but it will be at x8 speed as predicted, there is spacing enough for most cards, given they take up more and more space these days.

i'd say you are good to go, no need to upgrade the motherboard, now you will need to look at your power-supply to see if it will pull two of those beasts ;-)

will be awesome!

all the best from Down Under

PS: You may want to check if the 3080 will run SLI! as per Jake's message!

see this https://www.pcworld.com/article/357...n-slis-coffin-no-new-profiles-after-2020.html

RIP: Nvidia slams the final nail in SLI's coffin, no new profiles after 2020

A glaring fact jumped out at me while I was sifting through Nvidia’s product pages for our GeForce RTX 30-series vs. RTX 20-series spec comparison: Only the monstrous $1,500 GeForce RTX 3090 includes support for NVLink, the proprietary connector that enables SLI mult-GPU configurations. Even the $800 GeForce RTX 3080 lacks it, and Nvidia calls that graphics card the 30-series flagship. (The RTX 3090 is a “BFGPU” above and beyond the rest.) Given that Nvidia controls 80 percent of the graphics card market, it seems clear that the days of slapping multiple graphics cards into your PC to boost frame rates is effectively over.

I think you better get the big checkbook out and go for the 3090!

Thanks for the additional info, very helpful! I only use the GPUs to render with Redshift in C4D, is SLI really necessary for that? Also I was under the impression that I couldn't fit 2x2080 on my current board but maybe I just need a bigger case.

 

[Jerry James]

Thanks for the additional info, very helpful! I only use the GPUs to render with Redshift in C4D, is SLI really necessary for that? Also I was under the impression that I couldn't fit 2x2080 on my current board but maybe I just need a bigger case.

Technically you won't need NVlink if you just want to run 2 GPUs for Redshift. The NVLink connector only helps when you need access to a combined VRAM from both your GPUs for very large assets.

 

[Peter]

Technically you won't need NVlink if you just want to run 2 GPUs for Redshift. The NVLink connector only helps when you need access to a combined VRAM from both your GPUs for very large assets.

Thanks Jerry! Good news.
Do I need a new motherboard you think or can I just install 2x3080's?
Currently I have the ASUS Rog Strix X470-F Gaming.
Thanks in advance!

 

[Jerry James]

Thanks Jerry! Good news.
Do I need a new motherboard you think or can I just install 2x3080's?
Currently I have the ASUS Rog Strix X470-F Gaming.
Thanks in advance!

The motherboard has double-spaced PCI-E slots so you can install 2x3080s, no problem. However, the slots are PCI-E 3.0 x8 when using 2 GPUs so you will take a bit of a performance hit (3-5%) when rendering full-tilt using the GPU, especially if your VRAM buffer isn't large enough to hold your complete raw scene. In such cases, the PCI-E bus gets used a few times to swap data in and out, which affects performance. It's not a lot, but it's there. Certainly not worth upgrading your motherboard now though. Go for it.

 

[Peter]

The motherboard has double-spaced PCI-E slots so you can install 2x3080s, no problem. However, the slots are PCI-E 3.0 x8 when using 2 GPUs so you will take a bit of a performance hit (3-5%) when rendering full-tilt using the GPU, especially if your VRAM buffer isn't large enough to hold your complete raw scene. In such cases, the PCI-E bus gets used a few times to swap data in and out, which affects performance. It's not a lot, but it's there. Certainly not worth upgrading your motherboard now though. Go for it.

Thanks Jerry! I appreciate the explanation. I'd go for it but can't find any GPUs now. I'll wait until next year probably.

 

[Tived]

hi Jerry
3-5% penalty hit for pcie x16 to pcie x8 ? Are you sure you got these numbers correct? the theoretical difference is 50% or 100% depending which way look at it.

I would be interested in this too, as if I place multiple cards in x8 slots over x16 for rendering?

thanks

henrik

 

[Jerry James]

hi Jerry
3-5% penalty hit for pcie x16 to pcie x8 ? Are you sure you got these numbers correct? the theoretical difference is 50% or 100% depending which way look at it.

I would be interested in this too, as if I place multiple cards in x8 slots over x16 for rendering?

thanks

henrik

Hey Tived, the penalty only applies when your assets are large enough to require swapping in and out over the PCI-E bus and won't fit into the VRAM. With scenes that fit into your VRAM, there should be no performance difference

 

[xbigcheezx]

I can confirm Jerry's #s, it's not a huge hit during rendering, just loading assets onto the card. My last build had 4x 980ti's, the lane limitations at these levels are more on the cpu when you get to those levels.

SLI/NVlink not needed at all unless you are dealing with extremely large scenes.