1080 Ti SLI vs 2080 Ti

[Eutility]

Glad to see people starting to trickle over... just got here last night.

I just picked up a used 1080 Ti to use for SLI. I am questioning though should I sell it online (it's in great condition) or keep it. I have been obsessing over whether it is a wise move or not and I am realizing I will have to upgrade my PSU as it is just a tad too weak for an 8700k OXed and a pair of power hungry cards. I am a little nervous about using two PSUs in one PC with a add2psu adapter.

I realize that for most people the consensus has been for awhile that you should buy the best single card you can afford. Halifax I think and others have pointed out though how SLI is better taken advantage of with 3D Vision. At least a lot of the games I like seem to work with sli and 3D so it seems good. The downside being it wont work with VR except for a couple games.

In another thread Bo3b said that that driver compatibility may be an issue with the RTX cards. Does anyone here HAVE an RTX card? Because of Ngreedia's lame forum changes I no longer saw the signatures of people who I thought might have had them.

I am debating will the upgrade to a 2080 TI help 3D significantly like I saw moving from a 980 to a 1080 Ti.. or would that not compare to 1080 Ti SLI?

Concerned about frametime inconsistency being a bother. It will mostly be an LG Passive 4K 3D (ef9500) limited to 60 fps so that ought to help.

I am having to buy a refurb 1200W psu for $149 and at that plus the used waterblock cost ($180) I maybe should just say forget it and sell both cards and get a cheaper 2080 Ti I can add a waterblock to.

Seems like the difference between a single 2080 Ti and 1080 TI sli can be quite big in fps (though that is diminished by the inconsistent frametimes)

I wanted to wait for there to be Ti supers but those will probably be too expensive for awhile at least. And not sure about drivers working for them (which brings us back to ny original question about who has an RTX card they have been using with 3D vision and has it been working well).

Thanks

[Necropants]

I moved from 1080ti SLI to a 2080ti

Because SLI support is so poop on a game by game basis and the simple fact that SLI actually causes issues in 3dvision in some modern games like Tekken 7
I get better performance in the witcher 3 with a single 208ti in 3dvision despite good SLI scaling in that game.

Imo SLI is not worth it anymore. I would only consider it if you are running 3dvision surround. It causes more troubles than its worth even if you are technically probably doing a side upgrade.

[whyme466]

Yes, some people with newer RTX cards have reported issues with some fixes, since these cards apparently cannot use preferred older driver 425.31. I believe the issues are also related to use of newer Windows 10 OS like 1903 (1809 may be OK?). Some of this discussion appeared in Losti’s old NVidia forum thread about merging drivers.

When I had 980Ti SLI, I also experienced micro stuttering in games like Dark Souls 3. This annoying stuttering disappeared when I transitioned to single Pascal Titan X (1080Ti equivalent), with better performance. I currently have single hybrid cooled 2080Ti with my 4K 3D OLED E6 display - a superb combination. A single higher-performance GPU is also better for VR gaming than SLI, since so few VR games support SLI. Note that my Vive Pro and Index HMDs, when using something like 150% SS, can almost fully load my 2080Ti in some games, also.

[TimFx7]

I used SLI for 4 years. 980Ti SLI , 1080 SLI , 1080Ti SLI

You can follow SLI solutions for games that do not support SLI from this forum.
https://www.forum-3dcenter.org/vbulleti ... p?t=509912
It is German. however, google translate can automatically convert the page into English.

You will have to spend a lot of time with this software. (fort SLI settings)
https://github.com/Orbmu2k/nvidiaProfil ... r/releases

You may find yourself looking for solutions to "SLI" problems rather than playing games.
if you have so much time and patience. The most sensible solution in price-performance is the 1080ti SLI. but at some point your processor won't be enough. The higher the MHz you use CPu, the better performance you will get. that is, after SLI, you may need to buy a newer CPU....

I'm sick of dealing with SLI, so I sold my second card. It doesn't have enough power for 3D in 2080ti. This card doesn't deserve its money. (for 3D high-ultra settings) i will get 3000 series if i update my all rig in future...If the 3000 series does not run 3d, I'll buy a second-hand 2000 series in the future.

[guitarlickz]

I have 1080 ti SLI for about 2 years now..
it is true that there are only few aaa games supporting SLI and nowdays developers not doing much in this regard.
I mostly play on one 1080 ti but I have to lower the resolution to 1440p (on my 4k lg oled) to get a decent fps(40-60).
now im playing sottr in SLI directx 12 in 4k and I get a really good fps..around 45-60.. im sacrifing half of the horizontal resolution with SBS but still its amazing.
fortunately this is the exception to the state of SLI nowdays. there is no support for SLI. and im considering selling both and buying the 2080ti.

[Eutility]

Thanks for the feedback, it seems fairly unanimous. I tried to play around with it and decided, quickly, especially after your feedback, that it was just too much trouble on top of 3D Vision. If I kept trying to succeed in both I might throw up my hands in frustration completely!

I was super tempted based on good Skyrim SLI videos but you're right, it doesn't seem worth the headache.

[Necropants]

I have better performance in skyrim now with a single 20180ti than I ever could get 1080ti SLI to work with it, and on top of that it introduced a poop load of headaches to boot =)
Only caveat is if you ever wanted to run 3 screens for 3dsurround.

[Eutility]

That's great to hear since Skyrim is one of the most important games to me.

[Necropants]

Yeah note my version of Skyrim is max loaded to 254 mods as well a lions share of them graphics.
But in the case of skyrim it's very CPU bound.

[P.C.Zen]

If SLI would work for you, you might want to aim for two 2070 Super in SLI. The 2070 Super supports SLI.

[Eutility]

Necropants that is awesome re: 254 mods. I lost my character unfortunately, I miss her (tears...) but prob best to just start over as it is nearly impossible to restore all the mods without a backup.
Got a fightstick recently and want to get MK11 and Tekken, SFV works without the now broken fix but is not optimal.

PC Zen, I think just a 2080 Ti is easier as stated above by others. Too much of a headache

[john105]

I already had one 1080 Ti and asked myself the same question: should I buy a second 1080 Ti for SLI, or replace it with a 2080 Ti. There are a lot of benchmarks for these 2 configurations online, but unfortunately all of them are for 2D. 3D Vision often behaves much differently than 2D, so it would be wrong to just assume that the performance difference in 2D would be proportional to the difference in 3D.

So I decided that the only way to decide is to do the benchmarking myself. I bought both a 1080 Ti and a 2080 Ti to do it and return one of them that I like less later. There's a thread on the Nvidia forum about most demanding games for 3D Vision https://www.nvidia.com/en-us/geforce/fo ... emanding-/ I decided to take 4 of the games mentioned there that have a built-in benchmark: GTA 5, Shadow of the Tomb Raider, Hitman 2 and Metro Exodus. The results surprised me a lot.

I used a Core i9-9900K (4.7 GHz turbo boost), DX11 and 1920x1080 for all tests. I did several runs for each mode and averaged FPS between them to make sure the result is consistent. All results are of course for 3D Vision mode.

GTA 5 (all settings on max, MSAA OFF (because it causes issues with 3D))
GTX 1080 Ti...........37.57
GTX 1080 Ti SLI.....50.82 (+35% compared to one 1080 Ti)
RTX 2080 Ti...........37.63 (same as one 1080 Ti)

Shadow of the Tomb Raider (all settings on max, anti-aliasing TAA and SMAA4x)
GTX 1080 Ti (AA: TAA)................52
GTX 1080 Ti SLI (AA: TAA)..........99 (+90% compared to one 1080 Ti)
RTX 2080 Ti (AA: TAA)................52 (same as one 1080 Ti)
GTX 1080 Ti (AA: SMAA4x).........42
GTX 1080 Ti SLI (AA: SMAA4x)...77 (+83% compared to one 1080 Ti)
RTX 2080 Ti (AA: SMAA4x).........48 (+14% compared to one 1080 Ti)

Hitman 2 (all settings on max)
GTX 1080 Ti (without 3D fix).........51.51
GTX 1080 Ti SLI (without 3D fix)...45.10 (-12% compared to one 1080 Ti)
RTX 2080 Ti (without 3D fix).........51.22 (same as one 1080 Ti)
GTX 1080 Ti (with 3D fix)..............45.17
GTX 1080 Ti SLI (with 3D fix)........39.18 (-13% compared to one 1080 Ti)
RTX 2080 Ti (with 3D fix)..............44.43 (-2% compared to one 1080 Ti)

Metro Exodus (all settings on max, shading rate 100%)
GTX 1080 Ti (without 3D fix).........30.97
GTX 1080 Ti SLI (without 3D fix)...43.81 (+41% compared to one 1080 Ti)
RTX 2080 Ti (without 3D fix).........40.90 (+32% compared to one 1080 Ti)
GTX 1080 Ti (with 3D fix)..............20.02
GTX 1080 Ti SLI (with 3D fix)........28.13 (+41% compared to one 1080 Ti)
RTX 2080 Ti (with 3D fix)..............23.97 (+20% compared to one 1080 Ti)

The most interesting thing here is the 2080 Ti was never able to beat the 1080 Ti SLI, except for Hitman where SLI is slower than a single card. But even in Hitman, a 2080 Ti wasn't better than one 1080 Ti. SLI can be hit or miss. Sometimes it gives almost 100% FPS increase, and sometimes can make the performance even worse than a single card. You should also note that SLI doesn't always just work. For example, I needed to import a profile using Nvidia Inspector for Tomb Raider. Maybe Hitman can also be improved, but I couldn't find any SLI profiles for it.

My overall conclusion is the RTX 2080 Ti is a waste of money SLI does make sense, but only for some games. Another thing is what bo3b mentioned in another thread about the ability to go back to an older driver in case a particular game has issues. This is where the GTX 1080 Ti also wins. Based on all of this I made a decision to return my 2080 Ti and keep the second 1080 Ti. I realize that SLI has issues as mentioned in some posts above. My thinking is in the worst case, I can always disable SLI for a game that doesn't like it. But it will still give a very nice performance boost for games where it works fine.

[Necropants]

Beside from raw performance. (as I know It's about time for a motherboard/cpu /memory refresh for me)
Note I do not really play any of those games in the benchmarks so they might just have decent SLI profiles and scaling. But on the whole even with profile tweaking and then added 3dvision into the mix I'd still take a single 2080ti unless you like constantly playing around with your configuration and profiles and not being satisfied. Most of the new game engines don't support it at all and the profile changes just introduce more problems.

Also why so low resolution? I wouldn't say it's worth going up to 2080ti unless you are gaming at least at 1440p.

One advantage of 1080ti SLI is the larger range of drivers but for the most part i'm getting more performance with this single card than I ever got with 1080ti SLI in most games. (witcher 3, Re2 engine, Unreal engine 4 ect)
Tekken turns green screen and most profile tweaks introduce glitches and visual artifacts /anomalies.
then you have the micro stutter and things will just get worse from here on out.

Thanks for doing the tests all the same, theres very little data about this anyway.

I am thinking of maybe trying SLI or Nvlink as it's now called again with 2080ti later down the line.

[john105]

I see your point. I also prefer plug n play solutions when possible. In the past I always preferred to go for the best single card I can afford because I knew SLI is a trouble. But it changed when Nvidia discontinued 3D Vision, which means I won't be able to just go and buy the future 3000 series.

So far my SLI experience is much better than I expected. Getting and installing a profile for Tomb Raider wasn't really difficult. GTA and Metro worked with SLI out of the box with no tweaking. I haven't noticed any micro stutter in games that I tried.

Maybe the results would be much different for different selection of games, but I wanted to do 1) the most demanding ones (hence the reference to the thread where it was discussed), 2) with built-in benchmark to make measuring performance easier for me. Another candidate for me was Battlefield 5, but unfortunately it doesn't have #2. If you have any suggestions for other demanding games with benchmarks, let me know. I still have a few days before I return the card, so I might try it.

Also why so low resolution? I wouldn't say it's worth going up to 2080ti unless you are gaming at least at 1440p.

I guess my definition of low is different. Something closer to 800x600 is low for me My monitor is 1080p and I didn't get a 1440p on purpose, because I prefer to max out settings, which is harder with higher resolution. As you can see from my results, even with 2080Ti/1080 Ti SLI some games can be a challenge at 1080p with max settings.

[russellk]

This is really interesting so thanks very much for posting the results

Did you do the 2080TI runs after all the 1080TI benchmarks and after a clean install or DDU of the drivers?

The reason I ask is just because it seems strange that the 2080TI and 1080TI single card results are so similar in most of the benchmarks. At first I thought you must be CPU limited, but somehow SLI 3D vision mode seems to sidestep that. There has been evidence in the past that SLI scales better with 3d vision, so although SLI scaling in 2d mode is very resolution dependent, maybe the 3d vision driver does still benefit from SLI more than you'd expect just from raw GPU performance differences.

I've skipped between SLI and non SLI and always believed that 3d vision does benefit in some specific way from SLI, over and above the gains in 2d. To me, your results show that.

Another interesting question, is does Turing SLI benefit even more due to the extra bandwidth of Nvlink? I know The Witcher 3 was hit hard in SLI 3d due to the bandwidth over the old SLI bridge. DSS implemented a fix specifically to mitigate that.
I was close to going 2xNvlink 2080 but it's a hard sell given all the profile issues plus the relative price of a 2080 v 2080TI and the default performance profile. Although as you know SLI/Nvlink is rarely supported out of the box, Turing does have extra flags in the driver for Nvlink which I assume could help.
Also, SLI will generally benefit disproportionately from any graphics options that shift the load to the GPU, such as higher AA settings.

[john105]

Did you do the 2080TI runs after all the 1080TI benchmarks and after a clean install or DDU of the drivers?

I did the 1080 Ti/SLI tests first, then uninstalled the driver, manually deleted C:\ProgramData\NVIDIA and C:\ProgramData\NVIDIA Corporation (this is where things like profiles and shader cache are stored), switched to the 2080 Ti, and installed the driver with the clean installation checkbox. I used 425.31 for all tests.

The reason I ask is just because it seems strange that the 2080TI and 1080TI single card results are so similar in most of the benchmarks. At first I thought you must be CPU limited, but somehow SLI 3D vision mode seems to sidestep that. There has been evidence in the past that SLI scales better with 3d vision, so although SLI scaling in 2d mode is very resolution dependent, maybe the 3d vision driver does still benefit from SLI more than you'd expect just from raw GPU performance differences.

Yes, I also found it a bit strange. I think you're right that I hit the CPU bottleneck in some cases, even though it should be less of an issue as I have a Core i9-9900K. But I do believe that SLI can sometimes sidestep the bottleneck.

I also did benchmarks in 2D to compare it with results from online reviews and make sure there's no problem with my 2080 Ti. Both the 1080 Ti and 2080 Ti were very close in 2D in GTA and Hitman, but this is the expected result for 1080p (see https://youtu.be/LxNixL0-7lo?t=77 and https://www.tweaktown.com/articles/8952 ... ndex5.html). In Tomb Raider the 2080 Ti was 18% faster, and in Metro 36% faster, so the performance advantage in 2D was still present as expected.

Another interesting question, is does Turing SLI benefit even more due to the extra bandwidth of Nvlink?

I can't say for sure for Turing SLI because I only tested one card. But at least with the 1080 Ti SLI, I tried GTA 5 with both one and two SLI bridges, and didn't see any significant difference. It means that even the bandwidth of one SLI bridge is enough, so I also wouldn't expect much benefits from even higher bandwidth of Nvlink.

[guitarlickz]

I already had one 1080 Ti and asked myself the same question: should I buy a second 1080 Ti for SLI, or replace it with a 2080 Ti. There are a lot of benchmarks for these 2 configurations online, but unfortunately all of them are for 2D. 3D Vision often behaves much differently than 2D, so it would be wrong to just assume that the performance difference in 2D would be proportional to the difference in 3D.

So I decided that the only way to decide is to do the benchmarking myself. I bought both a 1080 Ti and a 2080 Ti to do it and return one of them that I like less later. There's a thread on the Nvidia forum about most demanding games for 3D Vision https://www.nvidia.com/en-us/geforce/fo ... emanding-/ I decided to take 4 of the games mentioned there that have a built-in benchmark: GTA 5, Shadow of the Tomb Raider, Hitman 2 and Metro Exodus. The results surprised me a lot.

I used a Core i9-9900K (4.7 GHz turbo boost), DX11 and 1920x1080 for all tests. I did several runs for each mode and averaged FPS between them to make sure the result is consistent. All results are of course for 3D Vision mode.

GTA 5 (all settings on max, MSAA OFF (because it causes issues with 3D))
GTX 1080 Ti...........37.57
GTX 1080 Ti SLI.....50.82 (+35% compared to one 1080 Ti)
RTX 2080 Ti...........37.63 (same as one 1080 Ti)

Shadow of the Tomb Raider (all settings on max, anti-aliasing TAA and SMAA4x)
GTX 1080 Ti (AA: TAA)................52
GTX 1080 Ti SLI (AA: TAA)..........99 (+90% compared to one 1080 Ti)
RTX 2080 Ti (AA: TAA)................52 (same as one 1080 Ti)
GTX 1080 Ti (AA: SMAA4x).........42
GTX 1080 Ti SLI (AA: SMAA4x)...77 (+83% compared to one 1080 Ti)
RTX 2080 Ti (AA: SMAA4x).........48 (+14% compared to one 1080 Ti)

Hitman 2 (all settings on max)
GTX 1080 Ti (without 3D fix).........51.51
GTX 1080 Ti SLI (without 3D fix)...45.10 (-12% compared to one 1080 Ti)
RTX 2080 Ti (without 3D fix).........51.22 (same as one 1080 Ti)
GTX 1080 Ti (with 3D fix)..............45.17
GTX 1080 Ti SLI (with 3D fix)........39.18 (-13% compared to one 1080 Ti)
RTX 2080 Ti (with 3D fix)..............44.43 (-2% compared to one 1080 Ti)

Metro Exodus (all settings on max, shading rate 100%)
GTX 1080 Ti (without 3D fix).........30.97
GTX 1080 Ti SLI (without 3D fix)...43.81 (+41% compared to one 1080 Ti)
RTX 2080 Ti (without 3D fix).........40.90 (+32% compared to one 1080 Ti)
GTX 1080 Ti (with 3D fix)..............20.02
GTX 1080 Ti SLI (with 3D fix)........28.13 (+41% compared to one 1080 Ti)
RTX 2080 Ti (with 3D fix)..............23.97 (+20% compared to one 1080 Ti)

The most interesting thing here is the 2080 Ti was never able to beat the 1080 Ti SLI, except for Hitman where SLI is slower than a single card. But even in Hitman, a 2080 Ti wasn't better than one 1080 Ti. SLI can be hit or miss. Sometimes it gives almost 100% FPS increase, and sometimes can make the performance even worse than a single card. You should also note that SLI doesn't always just work. For example, I needed to import a profile using Nvidia Inspector for Tomb Raider. Maybe Hitman can also be improved, but I couldn't find any SLI profiles for it.

My overall conclusion is the RTX 2080 Ti is a waste of money SLI does make sense, but only for some games. Another thing is what bo3b mentioned in another thread about the ability to go back to an older driver in case a particular game has issues. This is where the GTX 1080 Ti also wins. Based on all of this I made a decision to return my 2080 Ti and keep the second 1080 Ti. I realize that SLI has issues as mentioned in some posts above. My thinking is in the worst case, I can always disable SLI for a game that doesn't like it. But it will still give a very nice performance boost for games where it works fine.

Hi john thanks for the comparison.
The similar results between the 1080ti ans 2080ti is probably due to cpu bottleneck. I will assume that doing the test in higher resolution like 4k will benefit the 2080ti.
So now, the question of profitability is whether you’re using low resolution screen or higher one like a 4k 3D tv.
I personally prefer playing on my ASUS 1440p in 1080p getting higher fps with max setting than on my 4k oled in 4k resolution. Playing in 1080p resolution on my 4k oled is out of the question because the picture is awful and also you’re losing more resolution in SBS or TB. So I’m using my oled only for my 3D photography hobby (the picture quality is insane on this tv).

So to summarize - if you have only 4k 3D tv or prefer higher resolution go for the 2080ti. If you have smaller screen like the 27” ASUS and you like better higher fps on max setting - stay with the 1080 tis in SLI.
Lately I was on the verge of selling my 2 1080 tis and buying 2080 ti. I’m staying with my 1080tis. - that’s the most reasonable thing to do.
Thanks again John for the very insightful comparison!

[Necropants]

I am currently running 2080ti SLI with nvlink on Windows10 1809 Latest nvidia driver (also tried last official supported driver) with 3dvision injected. It's a long story but my original card only had 2 DP and I need 3. So I have brought another and depending on results I will sell the old card.

So far things aren't looking good. Many games crash on startup with 3dvision enabled. I am not sure if it's Drivers or windows at this point.
3Dvision surround will no longer work at all and all and windows blue screens.

Spending this weekend tinkering and dealing with problems instead of gaming reminds me why I abandoned SLI in the first place. When it works it's amazing, it just seldom works or is supported adequately anymore.
That said only game so far I have really got any success with is running Witcher 3, I need to test more. Rise of the Tomb Raider won't even start in 3D with SLI on. But hey 3dmark says my computer is now in the top 1 percentile of results so that's something I guess. /facepalm

Bottom line is SLI support is only going to get worse going forward, not better. Developers simply don't put the effort to support it correctly. Outer Worlds for instance this weekend I was actually getting reverse scaling. =/. If you play alot of one game that has great SLI support then I guess it's worth it, they are getting few and far between though.

[JtG74]

Is it worth upgrading GTX 1080 to GTX 1080 Ti? At 1080p difference is only 10-15% but at 4K it's 20-30%. So what about playing 1080p 3D Vision. Should I expect only 10% fps increase on more.

[john105]

Is it worth upgrading GTX 1080 to GTX 1080 Ti? At 1080p difference is only 10-15% but at 4K it's 20-30%. So what about playing 1080p 3D Vision. Should I expect only 10% fps increase on more.

I only compared GTX 1080 and GTX 1080 Ti in GTA 5 that is more CPU-bound and in 1080p, so the difference wasn't big. But what's interesting is going from GTX 1080 to GTX 1080 Ti increases FPS much more (+6%) than going from GTX 1080 Ti to RTX 2080 Ti (+2%).

Here's the results of my GTA 5 tests with different CPU and GPU combinations:. All settings on max and 1080p.