SLI over Fourth-generation NVIDIA NVLink: would it have been better?

[magellan]

I had thought the last SLI capable Nvidia cards were using NVLink instead of the old SLI connectors. I remember seeing a test of the High-Bandwidth Bridge or SLI HB Bridge vs. the standard SLI bridge and it seemed it made a difference in FPS (I believe it was a 1080ti but I think they even tested a 980ti and found repeatable differences in FPS). Fourth generation NVLink is much more impressive and:
provides a 3x bandwidth increase on all-reduce operations and a 50% general bandwidth increase over the prior generation NVLink with 900 GB/sec total bandwidth for multi-GPU IO operating at 7x the bandwidth of PCIe Gen 5.

Has anyone tried SLI w/3090 or 3090tis?

 

[EarthDog]

For all intents and purposes, multi-gpu is dead for the home consumer/gamer..for a few years/couple of generations now.

While there may be more bandwidth available in NVlink, I dont imagine it's obvious to see what the additional bandwidth does... in order to test, you'd need the same card but with 3rd and 4th gen links to see. There's no doubt 3000 series in SLI will be faster than 1000/2000 series, but I'm unsure how to isolate that bandwidth versus the previous gen. This is data center/HPC stuff, bud.

That said, for gaming, I dont recall gaming tests showing significant improvements in the first place... even at 4k where you'd think it could use the speed.

Tested: The payoff in buying Nvidia’s $40 SLI HB Bridge

Nvidia says you need the SLI HB Bridge to get optimum performance from dual GeForce GTX 1080 GPUs. We want to know what the benchmarks say.

www.pcworld.com

NVIDIA GeForce GTX 1080 SLI Review

Crysis 4K at more than 60 FPS! We take a close look at multi-GPU SLI with two GeForce GTX 1080 cards in 16 games and at 4 resolutions. We used an SLI HB bridge for all testing, but also have numbers with the old bridge to find out whether a high-bandwidth bridge is absolutely necessary for SLI...

www.techpowerup.com

Even if it was better, for home consumers or gaming, I just dont see the point when a single card can do the job (4k/120+, 2k/240hz+, 1080p 240hz+). Multi gpu doesn't work all the time or scaling is rarely close to 2x (and typically only at 4k)... between the increase in cost (double!) power use, noise, and inconsistent effectiveness, it's gone the way of the dodo.

 

[magellan]

This is the video I found testing the HB SLI bridge w/a 980ti and 1080, the most surprising result is what difference the HB SLI bridge brought to Fallout 4 using 1080s: a 24% increase in min. FPS at 4K.

Here's another article testing GTX 1080's w/the HB SLI bridge:
https://www.pcworld.com/article/415364/tested-the-payoff-in-buying-nvidias-40-sli-hb-bridge.html

One more article this time testing two Titan X Pascals with and without the HB SLI bridge:
https://www.tomshardware.com/reviews/nvidia-sli,4746-9.html

 

[EarthDog]

Yep... they all pretty much say the same thing... works on some games, not all.

RIP SLI

 

[MaddMutt]

What about the generic hard 2x sli bridges that come in the MB box?? They say HB SLI on the item but don’t have metal ends??

 

[freeagent]

I liked SLI when it worked, RIP indeed.

I did go through a few PSU's though..

 

[MaddMutt]

IIRC is was great if the game you played used it (+80%) BUT sucked if not ( 0%).