3090 vs 2х 2080ti

[OhYou_]

prob already can guess the answer, but what is better, the rtx 3090 or two rtx 2080ti?
I accidentally ended up with all three gpus last year because I was intending on buying the 2080tis from a friend but then I also got the slightly damaged 3090 in trade for some work, so I just used that but still had to buy the 2080tis.

Is it worth swapping them in to try? I also have the high bandwidth nvlink bridge, plenty of psu overhead, ect.
 

[igormp]

It depends on what you're going to use those for.

Games? Not at all.

[Blasty Blosty]

3090, NVLink is dead as a doornail

[bobby3dse]

4 minutes ago, OhYou_ said:

prob already can guess the answer, but what is better, the rtx 3090 or two rtx 2080ti?
I accidentally ended up with all three gpus last year because I was intending on buying the 2080tis from a friend but then I also got the slightly damaged 3090 in trade for some work, so I just used that but still had to buy the 2080tis.

Is it worth swapping them in to try? I also have the high bandwidth nvlink bridge, plenty of psu overhead, ect.
 

Please don't use SLI

[OhYou_]

oof ok, i thought the 20 series had some weird checker board method of sli and tons of advances that is incomparable to older sli tech tho

[emosun]

it depends if the application you use supports multiple gpu's.

3 minutes ago, igormp said:

Games? Not at all.

wow every game huh? lol. love seeing this blanket statement , always fun

[Blasty Blosty]

Just now, emosun said:

wow every game huh? lol. love seeing this blanket statement , always fun

Even if there was a difference, it's not worth the extra power draw or the headaches getting it to work

[venomtail]

SLI is dead. Just get the one card. Linus even had a video a few days ago where even 4 2080TI barely had a difference to a single 2080TI. Considering the extra costs and power consumption, even a worse deal.

[OhYou_]

Just now, venomtail said:

SLI is dead. Just get the one card. Linus even had a video a few days ago where even 4 2080TI barely had a difference to a single 2080TI.

link? I must have missed that one

[Agall]

12 minutes ago, OhYou_ said:

prob already can guess the answer, but what is better, the rtx 3090 or two rtx 2080ti?
I accidentally ended up with all three gpus last year because I was intending on buying the 2080tis from a friend but then I also got the slightly damaged 3090 in trade for some work, so I just used that but still had to buy the 2080tis.

Is it worth swapping them in to try? I also have the high bandwidth nvlink bridge, plenty of psu overhead, ect.
 

SLI is poo and died for a reason.

[venomtail]

11 minutes ago, OhYou_ said:

link? I must have missed that one

 

Sure there's a slight old CPU bottleneck so not 1:1 but still relevant as usage should have changed. 

[OhYou_]

Just now, venomtail said:

 

those are 980ti
the 2080ti is way different

[emosun]

Just now, Agall said:

SLI is poo and died for a reason.

wow every implementation of it huh? just right across the board. every card , every game , every decade. I'm amazed you ran every single setup though , that must be a world record you've broke. Owning and testing every single multiple gpu configuration and bit of software.

[OhYou_]

3 minutes ago, Agall said:

SLI is poo and died for a reason.

tbf my only experience with multigpu was using two ati cards from 2011 in crossfire, and I played crysis and minecraft, and both saw a massive performance improvement.
I guess the performance improvement is much less now then it seems

[venomtail]

5 minutes ago, OhYou_ said:

those are 980ti
the 2080ti is way different

Wtf am I smoking. Gotta get my eyes checked.

[Agall]

3 minutes ago, emosun said:

wow every implementation of it huh? just right across the board. every card , every game , every decade. I'm amazed you ran every single setup though , that must be a world record you've broke. Owning and testing every single multiple gpu configuration and bit of software.

Yes, precisely, I even used my bag of holding to conceal an infinitely large heatsink that allowed me to run every card regardless of the generation at 6.9GHz.

 

Just now, OhYou_ said:

tbf my only experience with multigpu was using two ati cards from 2011 in crossfire, and I played crysis and minecraft, and both saw a massive performance improvement.
I guess the performance improvement is much less now then it seems

Last time I daily drove an SLI setup was a set of GTX 780ti Classified's that I OC'd to 1.33GHz. The main limitation being micro-stuttering.

 

Sure, they might've improved it by this point, but I imagine it gets worse as you go up in framerate and with the dramatic improvements to display technology since it was relevant. Back then, I had a G-sync modded VG248QE, so pretty much the best display you could get in 2014, and micro-stuttering was likely more noticeable because of that. I wouldn't doubt with today's even better display technology if it wasn't more noticeable.

 

If you want to do it and report back how terrible it is though, go for it. There's ways to mitigate micro-stuttering involving locking framerate, reducing frame buffer, etc, I just don't think its worth it. Its hard enough finding modern motherboards that properly support SLI that aren't negotiating one card's PCIe lanes through the chipset.

[OhYou_]

ehh I ended up looking up a ton of data, and if the game actually scales with sli, its about a 25-30% improvement over one single 2080ti
so the 3090 is on average 23% more than the 2080ti in games, and that means it is only 2-7% slower than 2х 2080ti on average.
and the games that do not scale all seem to perform worse up to 15% vs a single 2080ti

eee ok

[igormp]

1 hour ago, OhYou_ said:

oof ok, i thought the 20 series had some weird checker board method of sli and tons of advances that is incomparable to older sli tech tho

Pretty irrelevant, the performance jump to a 3090 outweighs any possible gain in an 2080ti SLI setup (and more often than not it'll just not work to begin with).

 

Keep in mind that dual GPUs nowadays are mostly meant for compute. Even the NVLink in the 2080ti is mostly meant for that, SLI was just an afterthought.

1 hour ago, emosun said:

wow every game huh? lol. love seeing this blanket statement , always fun

Yes, every game, no exception. Feel free to disprove me, but this is one of the few cases where a blanket statement is more than enough.

[OhYou_]

After some careful consideration, the answer was clear.

Throw all three cards in

[OhYou_]

yeah it sucks
~28% usage on second gpu.
 

[igormp]

Blender could make use of all of those GPUs, or if you want to train some fancy models with 46GB of vram lol

[Blai5e]

I ran SLI'ed w/cooled 1080TI's (EVGA SC2's) for a long while and bought an EVGA 3090 FTW3 Ultra which I also watercooled. In most cases, the 3090 outperformed it plus it has 2nd-gen Ray Tracing, Video Super Sampling and DLSS 3. There were a few edge cases (mostly older games and some benchmarks like Firestrike) where the SLI setup "out-rastered" the 3090 though.

 

@OhYou_ - don't forget that with the RTX-3090 you get 24GB of GDDR6X whereas the RTX-2080TI is 11GB of GDDR6 which may prove advantageous with some game titles.

[8tg]

Really depends on the scenario. If you were mostly just playing older AAA games, the SLI 2080ti’s would completely smash a 3090.

For most other games, the 3090 will do better.

Other tasks which would be able to use multiple gpus independently would be a different story, where if the choice was one or the other, the 2080ti’s win again. Though not of vram quantity is a concern, where the 3090 pulls ahead with simply more vram.

But then at that point, just toss all 3 in there, which you have done. So if you have some heavy vray rendering to do, all 3.

 

Try something like GTA V or Crysis 3, or even older try battlefield 4, if you want to see SLI scaling with two cards go through the roof.

BF4 is one of very few games which can hit over a 100% performance increase with two cards, depending on the system as a whole. I think two 2080ti’s would be so horrendously overkill to that game that it would just run out of things to make them do, but two GTX 970’s smashed that game.

[OhYou_]

well unfortunately I did not get much testing in because the pc broke
after a bit of messing around with the three cards with LLMs since lol 46gb vram, it shut off and would no longer boot windows.
it would just crashed right at the windows logo
it would boot with no oc and I then figured test like one game in it which was mid because no 40% oc, and then it crashed after a while, so I pulled the cards out and went back to single 3090 and the issue stayed.

I gave up life for like 4 days till now I did a lot of testing and I'm about 60% sure its the ram because its stable with like 4 sticks of other ram even though the os only sees 3 because I probably have one in the wrong slot idk

I'm just gonna get new ram and not try that again idk. fairly sure with all three gpus this thing was capable of peaking at around 1850w on the 1600w psu so maybe that broke the ram if it did that

edit, it was the ram, i have no idea how but one half-died just in the presence of three gpus.
Maybe I'll mess with it when I get more ram but I want to get a shorter nvlink bridge or probably not run all the damn gpus at once

[Bagzie]

9 hours ago, OhYou_ said:

well unfortunately I did not get much testing in because the pc broke
after a bit of messing around with the three cards with LLMs since lol 46gb vram, it shut off and would no longer boot windows.
it would just crashed right at the windows logo
it would boot with no oc and I then figured test like one game in it which was mid because no 40% oc, and then it crashed after a while, so I pulled the cards out and went back to single 3090 and the issue stayed.

I gave up life for like 4 days till now I did a lot of testing and I'm about 60% sure its the ram because its stable with like 4 sticks of other ram even though the os only sees 3 because I probably have one in the wrong slot idk

I'm just gonna get new ram and not try that again idk. fairly sure with all three gpus this thing was capable of peaking at around 1850w on the 1600w psu so maybe that broke the ram if it did that

edit, it was the ram, i have no idea how but one half-died just in the presence of three gpus.
Maybe I'll mess with it when I get more ram but I want to get a shorter nvlink bridge or probably not run all the damn gpus at once

Where they all under load at any point and if so why?