Why is it not possible to do 5/6-way sli? (Or is it?)

[AtticusRed]

I see a lot of speculation, but I'm not able to find any evidence or testing with 5/6-way sli. If we had a sli bridge, a 6 slot mobo, and the drivers, why exactly isn't it done? Forget the convenience of it.

[Starelementpoke]

1 minute ago, NickolasStone said:

I see a lot of speculation, but I'm not able to find any evidence or testing with 5/6-way sli. If we had a sli bridge, a 6 slot mobo, and the drivers, why exactly isn't it done? Forget the convenience of it.

Because they performance gains at that point aren't worth it. Also, not enough pcie lanes.

[iamdarkyoshi]

Nobody could get ahold of that many cards, linus owns them all.

 

But after 3 or 3 cards, the added speed us pretty small, plus the bandwidth limitations on the motherboard

[DXMember]

14 minutes ago, NickolasStone said:

I see a lot of speculation, but I'm not able to find any evidence or testing with 5/6-way sli. If we had a sli bridge, a 6 slot mobo, and the drivers, why exactly isn't it done? Forget the convenience of it.

1) because you don't have the drivers

2) we don't have drivers because - https://en.wikipedia.org/wiki/Amdahl%27s_law

3) Developers like Ubisoft and publishers like WarnerBrothers cannot be bothered with coding such games

a) but we can still hope that Explicit Multi Adapter in DX12 and Vulcan will change that if people like Oxide Games keep pushing the limits of these APIs

 

you can still use a bagillion of GPUs for compute both on Windows and on Linux they just won't be able to game all at the same time

for example look at Linux's video of 7 gamers 1 motherboard

or here http://arstechnica.com/security/2012/12/25-gpu-cluster-cracks-every-standard-windows-password-in-6-hours/

[Josephdalepi]

11 minutes ago, NickolasStone said:

I see a lot of speculation, but I'm not able to find any evidence or testing with 5/6-way sli. If we had a sli bridge, a 6 slot mobo, and the drivers, why exactly isn't it done? Forget the convenience of it.

biggest reason: scaling

at that level, the gains are basically nothing, and theres a worse problem

screen tearing and artifacting

it gets exponentially worse with more cards

no one actually uses more than 2 cards because of this

[piemadd]

10 minutes ago, Starelementpoke said:

Because they performance gains at that point aren't worth it. Also, not enough pcie lanes.

1. Plenty of Mobos hace more than 5 slots for pcie.

2. There are a few single-slot gpu's that don't need gpu's

3. I believe that you can put more than one bridge on a GPU. Though I'm not exactly sure.

[Allshevski]

1. Awful stuttering

2. There is no need for that much power

3. There are not to many CPUs with that amount of lanes

4. Pretty much nobody (except Linus) would but 6 cards

5. Almost no motherboards that could handle it

6. Any CPU will bottleneck them

[Starelementpoke]

2 minutes ago, Implosivetech said:

1. Plenty of Mobos hace more than 5 slots for pcie.

2. There are a few single-slot gpu's that don't need gpu's

3. I believe that you can put more than one bridge on a GPU. Though I'm not exactly sure.

I meant the pcie lanes supported by the cpu. Like how some only have enough for 2 at 8x.

[AtticusRed]

Has anyone found anything where they actually try it? It'd be interesting to see the numbers. 

[Allshevski]

2 minutes ago, Starelementpoke said:

I meant the pcie lanes supported by the cpu. Like how some only have enough for 2 at 8x.

Exactly. Also, CPU's will bottleneck it! Unless you have about $30,000 to spend on GPUs and some Xeons..

[DXMember]

2 minutes ago, Allshevski said:

1. Awful stuttering

2. There is no need for that much power

3. There are not to many CPUs with that amount of lanes

4. Pretty much nobody (except Linus) would but 6 cards

5. Almost no motherboards that could handle it

1. valid point, Ahmdal's Law at work

2. LOL, U WUT?

3. There is no reason why we cannot run all of them at x4 speeds and correct me if I'm wrong but enthusiast chips from Intel have 28 and 40 PCI-E lanes which would allow us to run 6 and 10 GPUs on those things and we're talking about enthusiast solution of course office PCs and console mudblods won't  be running solutions like that

4. We're talking about enthusiasts

5. We're talking about enthusiast hardware anyway and we have EATX just for that

[DXMember]

5 minutes ago, Starelementpoke said:

I meant the pcie lanes supported by the cpu. Like how some only have enough for 2 at 8x.

x8 is arbitrary constraint by Mr. Huang

we can use Cossfire XDMA over x4

[Allshevski]

1 minute ago, DXMember said:

1. valid point, Ahmdal's Law at work

2. LOL, U WUT?

3. There is no reason why we cannot run all of them at x4 speeds and correct me if I'm wrong but enthusiast chips from Intel have 28 and 40 PCI-E lanes which would allow us to run 6 and 10 GPUs on those things and we're talking about enthusiast solution of course office PCs and console mudblods won't  be running solutions like that

4. We're talking about enthusiasts

5. We're talking about enthusiast hardware anyway and we have EATX just for that

2. Unless you want that uber 500 FPS on any game, you don't need that. 

3. nvidia cards don't support x4 lanes AFAIK

4 & 5. We are talking about Linus.

[kemit_the_frog]

No one can do it because of how badass it would be... Therefor only LTT could to it.

 

[DXMember]

4 minutes ago, Allshevski said:

2. Unless you want that uber 500 FPS on any game, you don't need that. 

3. nvidia cards don't support x4 lanes AFAIK

4 & 5. We are talking about Linus.

2. You don't NEED a house or clothes to survive, some things are just highly desired with not much reason behind it - https://youtu.be/Nj4ixZE7EWo?t=1m17s

3. yes they don't but it's an arbitrary constraint by Mr. Huang, older cards supported it just fine and there are drivers that have been hacked to support it on keplers as well with benchmarks showing absolutely zero problems

4 & 5 yeah, but this hobby is still cheaper than collecting lambos and buggatis

[AtticusRed]

Let's include Crossfire in this too. Any difference there?

[piemadd]

1 minute ago, Allshevski said:

1. Awful stuttering

2. There is no need for that much power

3. There are not to many CPUs with that amount of lanes

4. Pretty much nobody (except Linus) would but 6 cards

5. Almost no motherboards that could handle it

Yeah, it would cost more than the 7-gamers one cup vid. He would need to get some Nvidia gpu's.

[Allshevski]

1 minute ago, DXMember said:

2. You don't NEED a house or clothes to survive, some things are just highly desired with not much reason behind it - https://youtu.be/Nj4ixZE7EWo?t=1m17s

3. yes they don't but it's an arbitrary constraint by Mr. Huang, older cards supported it just fine and there are drivers that have been hacked to support it on keplers as well with benchmarks showing absolutely zero problems

Just.. Put some sexy watercooling on it and it will be cool (akhem! ) enough. 

[Allshevski]

3 minutes ago, Implosivetech said:

Yeah, it would cost more than the 7-gamers one cup vid. He would need to get some Nvidia gpu's.

I mean.. If you are as rich as Linus, then you're welcome to argue in this topic! Enthusiasts are like "yeah, I know I don't need that but it looks cool so why not?"

But this makes me wonder why Quadros don't support it.. They are overpriced anyway!

[DXMember]

21 minutes ago, NickolasStone said:

Let's include Crossfire in this too. Any difference there?

Amdals Law, see wiki linked above

[DXMember]

14 minutes ago, Allshevski said:

I mean.. If you are as rich as Linus, then you're welcome to argue in this topic! Enthusiasts are like "yeah, I know I don't need that but it looks cool so why not?"

But this makes me wonder why Quadros don't support it.. They are overpriced anyway!

not for gaming

for compute there is no such limitations unless it's again proprietary to nVidia, Radeons and FirePros don't have such limitations that I can tell you

[Dabombinable]

Because as it is even 4 way SLI is pretty much pointless as the bridge required for SLI have a really low bandwidth, making SLI scale poorly (far worse than Crossfire).

[iamdarkyoshi]

22 minutes ago, Implosivetech said:

Yeah, it would cost more than the 7-gamers one cup vid. He would need to get some Nvidia gpu's.

I knew that these projects' names were "inspired" by the 2 girls 1 cup video, but I just realized that CPU rearranged is CUP. Glorious.

[Allshevski]

Everyone, watch this and then complain: 

 

[AtticusRed]

4 minutes ago, Allshevski said:

Everyone, watch this and then complain: 

 

A lot of people say the scaling is bad, but really, I've seen that 4th card take GTAV from 50fps to 65+ which is actually quite desirable for a lot of people. If that 4th card can do that, then the question is what that 5th or 6th card could do. Another 5fps? Another 10?