amd multi gpu advice

[eatthis]

is anybody actually running sli/crossfire? if im gpu bound which i think i am, would another card help? i have a 6800xt btw
ps frametime appears to be high 20s, i thought that was how long it takes trhe cpu to send each frame to the gpu but i read on a dcs page that hits how long the cpu is waiting for the frame FROM the gpu, ie more than 0 means gpu bottleneck

Edited October 22, 2023 by eatthis

[LucShep]

AFAIK, multi gpu (SLI / Crossfire) stopped working when version 2.7 got out in 2021, was it not? 
(last version where that was working was 2.56, I think)

DLSS is now available in latest OB 2.9, but it seems FSR will soon be also supported, so AMD GPU users may have a similar trick to mess with for better performance.

 

[eatthis]

5 hours ago, LucShep said:

AFAIK, multi gpu (SLI / Crossfire) stopped working when version 2.7 got out in 2021, was it not? 
(last version where that was working was 2.56, I think)

DLSS is now available in latest OB 2.9, but it seems FSR will soon be also supported, so AMD GPU users may have a similar trick to mess with for better performance.

 

fsr is in but its effectively useless right now, theres a few things im tweaking now, wel see what happens

 

[kksnowbear]

I have several SLI setups and they've worked as expected...

...but as per LucShep's comment above, it was broken ~2.7 update. It did work with 2.5.6 (actually LucShep told me how to make it work, for which I am still grateful).

Can't say about CrossFire, though, haven't tried that.

Good luck

Edited October 22, 2023 by kksnowbear

[Braunn]

End of Multi gpu rigs (SLI/Crossfire) was/is a common endeavor by the manufacturers. Back in the day while it was kinda working you could buy two lower tier gpus and have more performance than with a single top dawg gpu for less money. 

Guess what, there's more money in it for ie. Nvidia to sell you a 4090 and make $4-600 pure profit PER CARD. 

Edited October 24, 2023 by Braunn

[kksnowbear]

Yes, but it is not "dead" as uninformed people like to say...

Even if we discount SLI or Crossfire (proper) altogether, there is still "multi GPU" that I believe is already working, and being supported.  In fact, it's actually (in a way) less costly than even SLI/Crossfire, because all the signalling/data transfer is done over the PCIe bus - which has now become fast enough/has enough bandwidth to enable eliminating the 'bridge' connector.  So less hardware to buy (and those bridges had gotten very expensive...I know because I own several of both types).

As I mentioned I have several setups like this right now, and I've already seen where two 2070 Super cards can compete with a single 3090 (!) ...and at a *much* lower price (!!)

And, I can tell you first hand, all the bullsh!t from back in the day about stuttering was just exactly that, bullsh!t.  I've run many (many) multi-GPU setups over the years and never once saw any such thing that couldn't be attributed to other sources/causes.  It is not strictly due to having two GPUs.  Even though I've sat numerous people down in front of one of these machines to "test drive" it, not one has ever even mentioned stuttering (given that these were test subjects whose heads weren't already filled with crap from online because they hadn't studied SLI).  In the absence of such bias and preconceived notions, the 'reviews' from first hand user testing have been overwhelmingly positive.

In fact, the only negative has been that it doesn't always work - which is 100% because of the games, not the SLI technology itself.  If the technology works anywhere (which it clearly does) then there's absolutely no valid technical reason it cannot work everywhere - the experience related about DCS above illustrates this clearly: It worked well before the 2.7 changes to DCS (and I've seen/tested this myself, first hand).

Long live Multi-GPU/SLI/Crossfire/whatever it's being called this week...screw the haters!  If this were as 'dead' as the haters clamor about, then no one would be actively developing completely new implementations - yet they are.  Want proof?  If it weren't still happening, there would be nothing to discuss in this very thread - but here it is, nonetheless.

As far as the theory that GPU manufacturers don't want this to happen and therefore do things to stop it: This can certainly be true, but it won't matter:  While they can stop their own official support for both hardware (bridges and connectors) and software (driver support/protocols), they can't stop the resources that exist in the machine regardless (PCIe 5.0), and those approaches developed by others outside the GPU manufacturers' control, from doing whatever they want.

[BitMaster]

Vulkan's mGPU might be a thing if implemented as advertised*. Cross-vendor, cross-SKU, cross-everything and it should still work & benefit the experience.

I just have my doubts.

*Vulkan itself and the app devs

Edited October 28, 2023 by BitMaster

[kksnowbear]

38 minutes ago, BitMaster said:

Vulkan's mGPU might be a thing if implemented as advertised*. Cross-vendor, cross-SKU, cross-everything and it should still work & benefit the experience.

I just have my doubts.

*Vulkan itself and the app devs

 

Indeed.  I too will be anxiously waiting to see exactly how it works out...and I do acknowledge, of course, it could still go completely to hell!

But the technology is sound, already in place in some cases, and has a ton of potential.  I can't help but be excited