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1 X570 Board, 3 Gamers

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Anyone has this setup?

 

I am buying a new rig, 3900x or 3950x but can't decide which board to get.

 

I want to run 3 windows vm running at the same time, each with gpu and usb pass-through. 

 

Which board to get? looking at Asus X570e and x570 taichi. I see many of you use the arous but still run in tons of issue.

 

ideally, I want one 2060super or above on my main gaming vm and 2 1650super or 1660 super on the other 2vms. 

 

please share ur working setup and tweaks to make it work.

 

 

 

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Im not gonna lie... the performance of this would be terrible. The 3900x and 3950x both have a very limited amount of PCIe lanes... so after the 2nd GPU your performance will suffer horribly even if the motherboard has 3 full x16 slots. Most of the AM4 motherboards when you plug 3 GPUs into them, they will drop the first GPU to 8x, 2nd GPU to 4x, and last one to 2x or 4x only. 

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just checked, its 2 slots at 8x speed and 1 at 4x, as long as I can play 4k video and play some emulator games on the 3rd vm, it can still be very useful. to me at least.

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As someone currently fighting problems with pcie lanes, I hope you decided against this.  Server hardware would do this better.

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This can work. The issue is the third PCIE slot on most x570 or B550 boards uses the Chipset. If you do want to do this I would suggest PCIE Bifurcation of a single X16 slot into multiple slots. Now for this to work the board will need to support this and you will need to do your research. But you can find the parts for this at the following link:

https://riser.maxcloudon.com/en/

 

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On 9/11/2020 at 1:16 PM, mrjrp15 said:

This can work. The issue is the third PCIE slot on most x570 or B550 boards uses the Chipset. If you do want to do this I would suggest PCIE Bifurcation of a single X16 slot into multiple slots. Now for this to work the board will need to support this and you will need to do your research. But you can find the parts for this at the following link:

https://riser.maxcloudon.com/en/

 

Bifurcation while possible is a bit of a lash up.

 

Better to buy a board designed for 3x pcie x8 electrical. Benefits of PCIE gen 4 bandwidth.

 

Asus Pro WS X570-ACE

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6 hours ago, Decto said:

Bifurcation while possible is a bit of a lash up.

 

Better to buy a board designed for 3x pcie x8 electrical. Benefits of PCIE gen 4 bandwidth.

 

Asus Pro WS X570-ACE

That board would definitely do it.  But would his slot 3 would only get x4 from the cpu right?  8x+8x from the cpu to slot 1 and 2.  Would slot 3 be 8x to the chipset which would then be bottle necked to 4x by it's connection to the cpu?  Or would it be 4x to the cpu? There are 24 lanes for the 3950x and 4 of those are for the chipset.   -trying to understand myself so I may be way off here-.     

 But with the use case he stated and pcie 4 that would probably be fine.

Edited by aasberry

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7 hours ago, aasberry said:

That board would definitely do it.  But would his slot 3 would only get x4 from the cpu right?  8x+8x from the cpu to slot 1 and 2.  Would slot 3 be 8x to the chipset which would then be bottle necked to 4x by it's connection to the cpu?  Or would it be 4x to the cpu? There are 24 lanes for the 3950x and 4 of those are for the chipset.   -trying to understand myself so I may be way off here-.     

 But with the use case he stated and pcie 4 that would probably be fine.

As I understand, you get 2x8 lane  PCI-E 4.0 to the CPU slots and the chipset gets 4 lanes of PCI-E 4.0

 

The chipset then provides a x8 link to the 3rd GPU. The chipset connection is x4 PCIE 4.0 which is same bandwidth as x8 PCIE 3.0. This third slot bandwidth is shared with other devices but is currently the best option for 3 GPU as you get up to PCIE gen 3 x8 bandwidth depending on contention from other devices whereas other boards give you at best a 4x electrical connection so you are limited with a PCIE 3.0  GPU.

 

Theoretically, if your VM uses the 3rd slot, along with sata/nvme also on the chipset, direct memory transfers reduce requirements on the cpu link.

 

Bifurcation would give you x4 links at PCIE 3.0 as the gtx16x0 cards are pcie 3.0

 

Edited by Decto

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