Why Crossfire and SLi is no longer available?

[Hunter-]

Why dual-gpu era is dead since 2013-2014?For example,i miss time when HD 5970, HD 7990 or gtx 690 was present.
For me Multi GPU is fantastically useful for many, many things,is raw power in a single motherboard slot.I mean what is the reason behind discontinuing dual GPU cards?I want to understand.Since 2013 both company Radeon and GeForce stopped their production of multi gpu solution for consumers.Why they don't want to revive again this solution in present?They are focusing only on single core GPU card

[deadlou666]

Games just don't make use of multiple and for the price and how much more performance you'd get you were better off getting the higher performance gpu

[Zando_]

Multi-GPU in games is more effort to implement than it's worth. Single cards are so fast now that we can do away with 2+ GPU setups, and so AMD and Nvidia have.

[Kilrah]

Too many issues with it, too little support for it in general, too much work to maintain for a tiny user base,...

[jaslion]

It was never 100% functional

Was an additional cost to implement in games for basically almost no userbase

Big development cost for a low return

Single better card always was better than 2 mid cards

Was up to the dev to implement and maintain which meant no quality guarantee in the limited games that got it

 

For productivy its been tried over and over and even there there are only a small ammount of applications that use multiple gpus

 

So the cost for the extra devtime needed for these is simply not worth it in any market

[igormp]

26 minutes ago, Hunter- said:

I mean what is the reason behind discontinuing dual GPU cards?

Current GPUs use way too much power and require tons of cooling. Can you imagine a single PCB with 2x 4090s? Over 1kW peak usage and tons of heat to dissipate.

Games, the main target for those GPUs at the time, also don't play that well with mGPU since it's hard to keep everything in sync, so people just stopped caring about it.

 

For other uses tho, mGPU is still really useful, like machine learning, just plug 2 or more GPUs and have the workload distributed among them without many headaches.

28 minutes ago, Hunter- said:

,is raw power in a single motherboard slot

Get a PCIe splitter and you can have 2x x8 devices in a single x16 slot  

 

[Zando_]

16 minutes ago, igormp said:

Current GPUs use way too much power and require tons of cooling. Can you imagine a single PCB with 2x 4090s? Over 1kW peak usage and tons of heat to dissipate.

Power draw is completely irrelevant to why SLI/Crossfire was dropped. Cooling is a non-issue either, waterblocks exist.

 

My GTX 780 Classifieds will each pull over 300W, and they support 4-way SLI, so if I bought 2 more I could put those on my X58 Classified SLI 4-Way and have 1200W+ of GPU. Now imagine folks pushing these on water or LN2 for benchmark scores. Even my 2 on air with a stock X5675 hexacore pull 750W from the wall through an 80+ Titanium unit, so that's pretty close to the actual wattage draw of the components themselves.

 

The reasons SLI was dropped are the ones mentioned already, it didn't work great and single cards are now fast enough that there's no point in trying to make it work. Purely that, not because of power draw or heat or cost or really any other reason, the base tech just wasn't worth the effort as cards got faster.

[igormp]

46 minutes ago, Zando_ said:

Power draw is completely irrelevant to why SLI/Crossfire was dropped.

I was talking about mGPU in a single board, not mGPU as a whole, since those are still plenty used in professional scenarios.

[Zando_]

3 minutes ago, igormp said:

I was talking about mGPU in a single board, not mGPU as a whole, since those are still plenty used in professional scenarios.

Ahh. Yeah, could be a struggle with 4090s, 4080s or below should be doable (they look around 300W under normal load). AMD still makes dual-GPU single-PCB workstation parts with 200W GPUs (so 400W card total) and that's running stock. Go back a bit and you have the 475W Radeon Pro Vega II Duo, back further and you have the 295x2 that's 500W stock. And overclockable, a friend had two of them and pushed 'em with dual 1200W PSUs.

[igormp]

1 hour ago, Zando_ said:

AMD still makes dual-GPU single-PCB workstation parts with 200W GPUs (so 400W card total) and that's running stock.

Do they? I thought the pro duo was the last one, custom made for apple.

[ewitte]

Before DX12 this was implemented by Nvidia and AMD.  DX12 puts it in the developers hands, most of which can barely even release a complete game that doesn't need months or even years of patching just to be functional.

[Zando_]

1 hour ago, igormp said:

Do they? I thought the pro duo was the last one, custom made for apple.

Pro Vega II Duo and now a Pro W6800X Duo. 475W and 400W respectively, so 200-225W per GPU/VRAM combo. Likely limited by the cooler set up of Apple's MPX cards for noise sake, if noise weren't as much of a concern then either higher speed intake fans or a beefy axial cooler could dump more heat.

[Cavalry Canuck]

5 hours ago, deadlou666 said:

Games just don't make use of multiple and for the price and how much more performance you'd get you were better off getting the higher performance gpu

I wonder if the price case would still be true if SLI were still supported by all cards, given we now live in an age of $1200 4080s.

[igormp]

1 hour ago, Zando_ said:

Pro Vega II Duo and now a Pro W6800X Duo. 475W and 400W respectively, so 200-225W per GPU/VRAM combo. Likely limited by the cooler set up of Apple's MPX cards for noise sake, if noise weren't as much of a concern then either higher speed intake fans or a beefy axial cooler could dump more heat.

Didn't know about that second one, interesting. Are any of those available outside of purchase for the mac pro?

[Zando_]

2 hours ago, igormp said:

Didn't know about that second one, interesting. Are any of those available outside of purchase for the mac pro?

AMD's page for them only shows the Mac Pro, so those are likely made just for Apple. AMD makes a lot of one-off models of hardware like that. Point was just more that there are still dual-GPU single-PCB cards in production, with pretty high wattage draw, and even higher wattage overclockable ones used to be made. So thermals/power draw wasn't the killer issue for them, and doesn't block us from making them today. Just no point for gaming, as AFR has issues and any other solution to rendering frames on 2 GPUs has even more issues, so it's not worth implementing when a single card is fast enough.

[Mick Naughty]

Better for companies to appeal to the masses. Most people have low to mid range hardware. No reason to invest in keeping something alive if there isnt a big enough return. 
Especially see where cards are now. People have been complaining about card prices for years. They would continue to do so about stuff they coudlnt afford anyway. 

[igormp]

1 hour ago, Zando_ said:

So thermals/power draw wasn't the killer issue for them, and doesn't block us from making them today. Just no point for gaming, as AFR has issues and any other solution to rendering frames on 2 GPUs has even more issues, so it's not worth implementing when a single card is fast enough.

But they're not a thing in other places, not only for games. Nvidia doesn't make any dual GPU in a single PCB anymore, even though there are plenty of systems of theirs with 8, 16 and even more GPUs, and I still believe that's still due to power draw and cooling limitations.

[Zando_]

12 minutes ago, igormp said:

But they're not a thing in other places, not only for games.

That's fair, those Mac Pro ones are the last holdout I know of on the workstation side.

[thrasher_565]

well people use to sli cheap cards and that came with heat problems do to being too close. they did fix it and add more space but then gpus got fatter and fatter and tg was used instead. not only that cost of gpus went way up. why sell 2 cards at $1000 when you can sell a titan at that cost... and ya game were clear that they were coming out in unlpayable states that they would never get time to even think about sli. that and esports that dont need fast stuff was also focused on. then PHONE games... the time and moeny is now spent on micro transactions and phone games... also porting games from consoles probably has something to do with it too.

[igormp]

On 2/5/2023 at 1:40 AM, Zando_ said:

That's fair, those Mac Pro ones are the last holdout I know of on the workstation side.

Turns out nvidia just released such a gpu, with not only two, but four GPUs in a single pcb:

https://www.servethehome.com/nvidia-a16-with-4x-ampere-16gb-gpus-onboard-quick-look/

 

Those are likely meant for VDI, so not being used as a single gpu, but pretty interesting nevertheless.