The SLI information guide

[phaithrider94]

On 8/14/2014 at 1:37 AM, D2ultima said:

I swear if you SLI two GTX 960s, 970s, 980s or 1070s after reading this guide I will {REDACTED}.

well that answers one of my sli questions. lol 

[Russ_t]

@D2ultima

Hi new to forum old to life,   Probably a strange question but from what I could wade thru of this thread you are VERY likely to have an intelligent answer for it.

A while back I replaced my two 660ti cards (in sli) with a Titan Xp (obscenely expensive and paid more than retail). the question: can those two cards be put in the system as physics only cards? SLI with each other (not w/Titan) used as kinda math co-processors?  The worry is smoking a lot of gear!

 

Have been playing around with a lot of CUDA programming and would like to have all the processors to work with at once.

[Princess Luna]

3 minutes ago, Russ_t said:

.

To be perfectly frank if you have a nVidia TITAN Xp then don't bother with an ancient GTX 660 Ti it really won't help in any meaningful way and likely might actually hinder performance due to incompatibilities.

 

PhysX dedicated card is no longer an actual thing as well...

[D2ultima]

On 10/24/2019 at 2:50 PM, Russ_t said:

@D2ultima

Hi new to forum old to life,   Probably a strange question but from what I could wade thru of this thread you are VERY likely to have an intelligent answer for it.

A while back I replaced my two 660ti cards (in sli) with a Titan Xp (obscenely expensive and paid more than retail). the question: can those two cards be put in the system as physics only cards? SLI with each other (not w/Titan) used as kinda math co-processors?  The worry is smoking a lot of gear!

 

Have been playing around with a lot of CUDA programming and would like to have all the processors to work with at once.

It won't make any sense. SLI only functions as a way to make cards render separate frames, PhysX isn't accelerate-able by it. And even if it was, your Titan Xp will slow down to the card that is running PhysX, and 660Tis are likely to not do it nearly as fast. I would quicker toss a 1660 or 1660S at the job and running your second monitors, and you can use it for solid NVENC as well.

[Csshaz3]

This thread is as dead as SLI    I've run sli for the past 12 years. I've got two msi 960gtx's 4gb but one is dedicated to physics and pretty much just extra memory.

[D2ultima]

38 minutes ago, Csshaz3 said:

This thread is as dead as SLI    I've run sli for the past 12 years. I've got two msi 960gtx's 4gb but one is dedicated to physics and pretty much just extra memory.

If you're dedicating one directly to SLI and not using performance mode, that's not SLI... the memory does not stack (which you'd know if you actually read the guide :D)

That said, I have stated multiple times, updating this thread involves literally re-writing the entire thing from scratch because it was not written before the forum went to IPB4 and it has some... apparent compatibility issues. It frequently breaks spoiler tags and page colour among other things. I would probably have to create a new thread entirely to make it ease to edit/update, but that's just an extreme amount of effort and I'd need to get it re-pinned and whatnot.

[Csshaz3]

Wasn't calling you out on the thread man. Alot of that info is over my head. I utilize sli for games that can use it but it's mostly just the old ones. SLI in my vive doesn't work or I havent dug deep enough to get it properly working. Didnt know the memory stack issue. That sucks. 4gb is decent enough for what I'm doing thankfully. Cheers.

[D2ultima]

3 minutes ago, Csshaz3 said:

Wasn't calling you out on the thread man. Alot of that info is over my head. I utilize sli for games that can use it but it's mostly just the old ones. SLI in my vive doesn't work or I havent dug deep enough to get it properly working. Didnt know the memory stack issue. That sucks. 4gb is decent enough for what I'm doing thankfully. Cheers.

SLI won't do anything in the vive for your cards, you'd need Turing for NVLink to have enough bandwidth (but that'd still require them to code for it).

[Drakius]

Hi D2ultima!

 

I read your guide, I've been having such a hard time finding any info at all on x8 vs x16 when it comes to graphic cards, so your guide is an oasis in a desert of nothingness, great guide.

 

That said I've got a bit more of a specific inquiry that maybe you could give me your opinion on. The way I build PCs is I build one every 4 years, I go hard on it and don't touch or update it for the next 4 years (I like it this way, won't change this formula), so I have been going SLI for the past 8 years. This year I'm set on SLI 2080ti, which I will be playing on a 144hz 1440p g-sync monitor for the next 4 years (don't care for 4k, would rather have good frames).

 

That said the only thing I'm not sure on is the CPU/mobo combo. At first I was thinking 9900k, but after more research I came into PCI bandwidth (learn something new everyday uh) and how it might affect GPU performance. So then I thought, maybe the 9800x is better for me that way I get x16/x16 on my cards instead of x8/x8, though it's definitely not as good on gaming performance. But I'm also a realist and I know I won't get SLI to work on all my games, so is it better to go with the 9900k which has the best gaming performance on single cards (I know it'd run x8 single, but it might still be better because the 9900k is better for gaming? No clue, that's why I'm here!) or is the 9800x still the winner cause even with one card it'd run at x16, and of course the x16/x16 SLI benefits.

 

so what do you think I should get for my set up? 9900k? 9800x? Something else entirely? I heard the 10th gen x-series stuff might be coming out this month, (IE: 10900x and such) is that any good for my needs? (not really interested going into AMD this year and would rather stick to under $1000 on the CPU budget) Sorry for the drawn out post, really would appreciate any input.

[D2ultima]

9 hours ago, Drakius said:

Hi D2ultima!

 

I read your guide, I've been having such a hard time finding any info at all on x8 vs x16 when it comes to graphic cards, so your guide is an oasis in a desert of nothingness, great guide.

 

That said I've got a bit more of a specific inquiry that maybe you could give me your opinion on. The way I build PCs is I build one every 4 years, I go hard on it and don't touch or update it for the next 4 years (I like it this way, won't change this formula), so I have been going SLI for the past 8 years. This year I'm set on SLI 2080ti, which I will be playing on a 144hz 1440p g-sync monitor for the next 4 years (don't care for 4k, would rather have good frames).

 

That said the only thing I'm not sure on is the CPU/mobo combo. At first I was thinking 9900k, but after more research I came into PCI bandwidth (learn something new everyday uh) and how it might affect GPU performance. So then I thought, maybe the 9800x is better for me that way I get x16/x16 on my cards instead of x8/x8, though it's definitely not as good on gaming performance. But I'm also a realist and I know I won't get SLI to work on all my games, so is it better to go with the 9900k which has the best gaming performance on single cards (I know it'd run x8 single, but it might still be better because the 9900k is better for gaming? No clue, that's why I'm here!) or is the 9800x still the winner cause even with one card it'd run at x16, and of course the x16/x16 SLI benefits.

 

so what do you think I should get for my set up? 9900k? 9800x? Something else entirely? I heard the 10th gen x-series stuff might be coming out this month, (IE: 10900x and such) is that any good for my needs? (not really interested going into AMD this year and would rather stick to under $1000 on the CPU budget) Sorry for the drawn out post, really would appreciate any input.

NVLink SLI makes x8/x16 moot, unless in the last month Nvidia used a driver update to limit the bandwidth from the cards, so the only time it'd matter is if a game hates a SINGLE card being on x8 for some reason.

[Drakius]

14 hours ago, D2ultima said:

NVLink SLI makes x8/x16 moot, unless in the last month Nvidia used a driver update to limit the bandwidth from the cards, so the only time it'd matter is if a game hates a SINGLE card being on x8 for some reason.

Interesting, why is that? If I'm reading your guide right, x8 vs x16 wasn't ever the issue, it's just the bandwidth between the cards in SLI, and since NVLink uses a lot more bandwidth, then it renders the whole x8/x16 thing moot, correct?

 

Therefore technically then I should just go with the 9900k if I'm going to SLI 2080ti with NVLink for mostly gaming purposes? The only time it'd matter is if a game doesn't like being on x8 for a single card when I can't get it to run SLI? Are there a lot of games like that, or is that a rarity?

 

According to this review https://www.techpowerup.com/review/nvidia-geforce-rtx-2080-ti-pci-express-scaling the scaling seems pretty close for games, except like Hellblade, Wolfeinstein 2 and Prey at 1440p, which seem to lose 12ish FPS each. Is that what you meant by some games not liking single x8 cards? Or are there much worst example, because if ~12ish FPS is the worst of it, I feel like I'd just "recuperate" those frames from using the better gaming CPU that is the 9900k over the 9800x (that I'd need to run x16) for example, if that makes sense. Or am I way off base here with that assumption?

[D2ultima]

11 hours ago, Drakius said:

Interesting, why is that? If I'm reading your guide right, x8 vs x16 wasn't ever the issue, it's just the bandwidth between the cards in SLI, and since NVLink uses a lot more bandwidth, then it renders the whole x8/x16 thing moot, correct?

Correct

11 hours ago, Drakius said:

Therefore technically then I should just go with the 9900k if I'm going to SLI 2080ti with NVLink for mostly gaming purposes? The only time it'd matter is if a game doesn't like being on x8 for a single card when I can't get it to run SLI? Are there a lot of games like that, or is that a rarity?

Correct, and it is a rarity, the only games I could think of that might do it are Dirty Bomb and Ark: Survival unoptimized. And those are just my guesses, since both games run pretty different even on same-hardware PCs, I couldn't say. They have always run exceptionally badly for me on single GPU though.

 

11 hours ago, Drakius said:

According to this review https://www.techpowerup.com/review/nvidia-geforce-rtx-2080-ti-pci-express-scaling the scaling seems pretty close for games, except like Hellblade, Wolfeinstein 2 and Prey at 1440p, which seem to lose 12ish FPS each. Is that what you meant by some games not liking single x8 cards? Or are there much worst example, because if ~12ish FPS is the worst of it, I feel like I'd just "recuperate" those frames from using the better gaming CPU that is the 9900k over the 9800x (that I'd need to run x16) for example, if that makes sense. Or am I way off base here with that assumption?

I was thinking about a much more significant drop in performance, like I could barely hold even 60 flat in dirty bomb regardless of settings sometimes when I used to try it, and my GPU usage was low as hell and my PC had ample other performance leftover no matter what I did. The devs couldn't seem to figure out what my issue was either. Thinking back on it now, it might have been that, but I have no way of checking since I cannot force my GPUs to x16 in my laptop and I don't yet have a desktop to check with. You really shouldn't worry about it, you can always turn off the slot and get x16 properly if you must play one of those games on a desktop (assuming your board is half decent anyway)

[Drakius]

1 hour ago, D2ultima said:

Correct

Correct, and it is a rarity, the only games I could think of that might do it are Dirty Bomb and Ark: Survival unoptimized. And those are just my guesses, since both games run pretty different even on same-hardware PCs, I couldn't say. They have always run exceptionally badly for me on single GPU though.

 

I was thinking about a much more significant drop in performance, like I could barely hold even 60 flat in dirty bomb regardless of settings sometimes when I used to try it, and my GPU usage was low as hell and my PC had ample other performance leftover no matter what I did. The devs couldn't seem to figure out what my issue was either. Thinking back on it now, it might have been that, but I have no way of checking since I cannot force my GPUs to x16 in my laptop and I don't yet have a desktop to check with. You really shouldn't worry about it, you can always turn off the slot and get x16 properly if you must play one of those games on a desktop (assuming your board is half decent anyway)

Alright I think I'm decided I'll be going with the 9900k for my 2080ti SLI build this year. I don't plan on cheaping out on the mobo. The MSI meg z390 ace seems to have good reviews, might go with that one. Hopefully it has an option to turn off one of my PCI lanes and force x16 on a single card if I do run into one of those rare games.

 

I'm glad I found your guide, really help put my mind at ease, especially with your input. Much appreciated! Thank you again.

[D2ultima]

On 11/24/2019 at 10:10 PM, Drakius said:

Alright I think I'm decided I'll be going with the 9900k for my 2080ti SLI build this year. I don't plan on cheaping out on the mobo. The MSI meg z390 ace seems to have good reviews, might go with that one. Hopefully it has an option to turn off one of my PCI lanes and force x16 on a single card if I do run into one of those rare games.

 

I'm glad I found your guide, really help put my mind at ease, especially with your input. Much appreciated! Thank you again.

Save your god damn soul and never buy a MSI motherboard. I'd suggest getting a Maximus X hero or barring that, a Maximus XI formula if you want to overclock a lot (I think formula is the one where they didn't destroy the VRM setup). USB BIOS flashback for updating for 9900K/KS/etc on Maximus X line.

 

You're welcome, I wish I could update them easily/properly on this forum.

[Drakius]

Had bad experiences with MSI motherboards I take it? That's strange, I've had an MSI motherboard and 2 MSI 980ti for my last build (the one I'm upgrading from) and I've never really had any issues, besides maybe the killer network manager giving me a memory leak once or twice over the last few years, and that was a fairly easy fix. And they seem to have good to great reviews the z390 ones.

 

What kind of issues have you run into with MSI mobos? I'll keep looking around maybe move away from a MSI mobo, still undecided though.

[D2ultima]

11 hours ago, Drakius said:

Had bad experiences with MSI motherboards I take it? That's strange, I've had an MSI motherboard and 2 MSI 980ti for my last build (the one I'm upgrading from) and I've never really had any issues, besides maybe the killer network manager giving me a memory leak once or twice over the last few years, and that was a fairly easy fix. And they seem to have good to great reviews the z390 ones.

 

What kind of issues have you run into with MSI mobos? I'll keep looking around maybe move away from a MSI mobo, still undecided though.

I haven't had a desktop in far too long, I just talk to a LOT of people who have custom PCs and are PC gamers. We have all agreed that until I tell people "buy MSI motherboard" they are to assume they don't exist as an option

[Drakius]

3 hours ago, D2ultima said:

I haven't had a desktop in far too long, I just talk to a LOT of people who have custom PCs and are PC gamers. We have all agreed that until I tell people "buy MSI motherboard" they are to assume they don't exist as an option

Fair enough! I'll probably go on a deep research today some more since it's pricey equipment all around, order later today or tomorrow. MIGHT go with an MSI board, might not, I'll keep your suggestion in mind.

[D2ultima]

On 12/3/2019 at 7:57 AM, Drakius said:

Fair enough! I'll probably go on a deep research today some more since it's pricey equipment all around, order later today or tomorrow. MIGHT go with an MSI board, might not, I'll keep your suggestion in mind.

Even if you do research, if you find a Maximus X hero or code, take it. NOT THE XI. The X. The BIOS is so far above and away with everything it's not even close to having competition at all.

 

That said, you need to look at people who have long-term boards. Look at problems with previous generation boards. Nobody gets boards that just go poof in 3 months where you can see a bunch of bad test data, you want long-term info. When companies have a track record of things conking out in a year or two. Otherwise, current overclocking data works, since people compare those to other boards right away and one doesn't need to see how long term ownership turns out.

[BCTech]

Good day,

 

hardware:

 

- 1x Thermaltake T900 case

- 1x Corsair HXi 1200 power supply

- 1x i9 9900k processor

- 1x Aorus Z390 Xtreme Waterforce motherboard

- 4x Trident Z Royal RGB DDR4 3000 16GB

- 1x Bitspower RAM water cool DIMM x4 RGB

- 2x 4 TB Samsung 860 QVO SSD (primary data drives in RAID)

- 2x 4 TB WD Black SATA (backup drives in RAID)

- 2x 2 TB Samsung 970 EVO Plus M.2 (OS Drives in RAID)

- 2x Bitspower waterblock 3.5” drive covers
- 1x EVGA GeForce RTX NVLink RGB Bridge - 3 slot

 

System Usage:  Photoshop 50%, Heavy Gaming 30%, Video Streaming 20%.

 

System Build Experience:  Intermediate

 

Question(s):

 

1. Do you see anything that would impede optimal performance?

 

2. Will a 3 slot Bridge work on this MB or should I go with a 4 slot?

 

3. I am planning on ordering 2x Aorus RTX 2080 Super’s for video and use NVLink... 

I have heard that the performance of NVLink for consumer grade video cards is only about 20% gain over standard SLI due to the bridge having to still operate in a master to slave configuration? Or, has the bridge and drivers been optimized to now allow in essence the doubling of the processing power due to it fully supporting NVLink and parallel processing like the commercial graphics cards?

 

thank you in advance for your time.

 

Gary

[D2ultima]

That machine looks like a large waste of money on your SSDs, PSU and RGB RAM coolers. There is no point to RAIDing nor NVMe SSDs, and QVOs are trash QLC NAND.

 

NVLink is a fix for when bandwidth is too low for optimum scaling. It is the difference between visual bugs/negative scaling/single digit % scaling without using PCI/e 3.0 x16/x16 + LED/HB bridges on previous gens. It is most useful when you force SLI on games that don't normally have a profile or give visual bugs in SLI, like Dragonquest XI, or which function badly in SLI like Witcher 3 with TAA enabled with minimal percentages increases.

 

Based on your question format and the way you've laid out your PC, you are not a high level user or an enthusiast who will spend a lot of time tinkering, so I'd just buy a single 2080Ti and call it a day.

[BCTech]

Thanks for the suggestion. I am a graphic designer and coder that is getting back into gaming after a many year focus on my career.

I like to tinker and want to build a water cooled system to see what Limits I can push it to, get a good foundation back into system design, and not have to replace hardware the next time a high demand game comes out.

[D2ultima]

On 1/20/2020 at 12:45 AM, BCTech said:

Thanks for the suggestion. I am a graphic designer and coder that is getting back into gaming after a many year focus on my career.

I like to tinker and want to build a water cooled system to see what Limits I can push it to, get a good foundation back into system design, and not have to replace hardware the next time a high demand game comes out.

Then get an ok video card now, and wait for the next generation stuff to come out which should be middle of this year people are assuming (I think so too, considering previous time frames of releases). Or a 2080Ti. I do not suggest SLI if you aren't gonna sit and tinker with NVPI and throw in a ridiculous amount of effort and time into figuring out profiles for games that don't otherwise support multi-GPU out the box.

 

Note: doing that CAN provide quite rewarding experiences, I know of multiple games (TW3, DQ 11, Betrayer, UT 4, R6S, etc) that function with benefits in SLI when you have excess bandwidth (preciously PCI/e 3.0 x16/x16 + LED/HB bridge, now simply NVLink) where they otherwise don't function at all, but you are going to have to use a lot of elbow grease and it isn't something I recommend to newbies or people just starting out. It WILL result in a lot of time spent not playing games getting them to work before you actually get to jump in and relax while gaming, so if that doesn't sound like something you're totally fine with, don't bother with mGPU at all.

[BCTech]

Thank you for the feedback, very constructive thank you. 

[The-Director]

Hello all,

 

I read the first post in the thread and then went to the latest posts and went back a few pages and I did not see my answer, so here it goes:

 

I have a 2070 super. Right now I could choose to upgrade to a 2080 ti (by selling the 2070) or I could buy another 2070 and sli link them.

 

from what I’ve found there can be a better performance boost using two 2070’s than just one 2080ti, though not all games can use this headroom.

 

Can someone confirm which would be the better/best choice? My main goal is gaming, with some secondary 3D rendering on Blender.

 

my current setup is i7 8770k. With 32gb ram. I try to play on a 4K monitor at 60 FPS.

 

bonus question, the two main games I am planning to buy this for is Star citizen and Cyberpunk. If you want to filter your answer with some hard detective work please do!

[Snowarch]

if one card dies in an sli setup, is the oher bricked? im on linux, and plan to try a p106 sli for gaming, or at least rendering. never done an sli before so i want to make sure if the second card dies, my system will not.

 

my specs right now;

gpu: p106 and coffee lake graphics on prime

ram: 16gb (2*8gb sticks) at 2133 speed rated 2400

cpu: 8086k stock

additional note: i can get 30-45 fps on a single p106 4k in modded games, want to make it 60.