Threadripper, PCI Express, and multiple GPUs

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Quartz-1

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One of the plus points of Threadripper - and Epyc - is the number of PCI Express lanes. I would like to see [H] test the effect of this with multiple GPUs, both Radeon and Geforce, in 2, 3, and 4 card configurations. I suspect that there will be a modest difference but I'd like actual numbers.
 
I doubt we will be spending resources on that. Assuming you are talking about gaming?
 
Sli and crossfire have really bad returns with anything over 2 cards and in some situations more than one.
 
And I wonder how much that is to do with the paucity of PCI Express lanes. Threadripper should be able to grant a full 16 lanes to each of three GPUs and Epyc 16 lanes to all four.
 
Old games run fine on a single 1070

Current games are not produced to take advantage of SLI

If you need all the GPUs for mining, genomics, AI, whatever R&D - a PCIe switch backplane + cheap host CPU w/IPMI is a better option (or Cloud if the utilization/economics make sense)

64 lanes are great future-proofing for a platform architecture that will last 5+ years, but in a server purchased today they are a solution looking for a problem
 
Quartz-1 said:
And I wonder how much that is to do with the paucity of PCI Express lanes. Threadripper should be able to grant a full 16 lanes to each of three GPUs and Epyc 16 lanes to all four.
Click to expand...

All current x399 boards are 16 8 16 8
 
This would only be for convenience of features. Take for instance, seing PCI-E slots dissabled due to another slot or an M2 slot in use, or lack of second or third M.2 slots, lack of sata ports.. etc..

You can't really benchmark that. Its a feature advantage, not a performance advantage
 
Would be useful for gaming in a 290 Quad Xfire vs 780ti Quad SLI showdown in BF4 from 2013.... where the video cards run out of memory faster than the performance increase at 4K.
 
I don't see multiple cards for gaming as that important now. Unless future VR tech with high resolution displays and 90 fps or faster is out, and two cards from the ground up supports this.

I do see two or more gpus today useful for compute type work, 3D rendering using GPU quality has greatly improved. Video production and other type of workloads. Basically professional workstation work and HEDT.
 
noko said:
I don't see multiple cards for gaming as that important now. Unless future VR tech with high resolution displays and 90 fps or faster is out, and two cards from the ground up supports this.

I do see two or more gpus today useful for compute type work, 3D rendering using GPU quality has greatly improved. Video production and other type of workloads. Basically professional workstation work and HEDT.
Click to expand...


My sli 1080ti makes vr buttery smooth along with the games that support it but.... not worth more than two cards period. Id rather just run 2 anyways. Makes it easier for devs to really focus on its support.
 
KazeoHin said:
This would only be for convenience of features. Take for instance, seing PCI-E slots dissabled due to another slot or an M2 slot in use, or lack of second or third M.2 slots, lack of sata ports.. etc..

You can't really benchmark that. Its a feature advantage, not a performance advantage
Click to expand...

on threadripper nothing gets disabled. You can have 2 gpu at 16 x and 3nvme at 4x each and still have 16 more lanes for slots/motherboard cpu requirements.
 
Quartz-1 said:
One of the plus points of Threadripper - and Epyc - is the number of PCI Express lanes. I would like to see [H] test the effect of this with multiple GPUs, both Radeon and Geforce, in 2, 3, and 4 card configurations. I suspect that there will be a modest difference but I'd like actual numbers.
Click to expand...

Vega (the user) has a post someplace on these forums from a little while back. PCIe 3.0 8x to 16x increases performance by 14% IIRC for SLI.

But mGPU is garbage. Past two cards never made sense and mGPU makes less and less sense at all. Once the Volta Titan drops it'll be such a tiny tiny niche with ever less support.
 
Dayaks said:
Vega (the user) has a post someplace on these forums from a little while back. PCIe 3.0 8x to 16x increases performance by 14% IIRC for SLI.

But mGPU is garbage. Past two cards never made sense and mGPU makes less and less sense at all. Once the Volta Titan drops it'll be such a tiny tiny niche with ever less support.
Click to expand...

Yep, and then Navi will come out and there goes any reason for crossfire to be well supported either. :( Crossfire is supported on a few newer games now more than SLI but, if I did the research, I would probably find that most new ones don't support it then do. (Rise of the Tomb Raider supports it well but, not much else new does.)
 
Does anyone ever need more than dual 1080tis OCd?
 
gigatexal said:
Does anyone ever need more than dual 1080tis OCd?
Click to expand...
Maybe if you are running triple monitors or 4K and want the settings on max?
I run my little 980ti with a 4K and some settings have to be down, but it plays fine. VR doesn't need much yet, but the next version will I bet.
 
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