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Hi all,

I would like to set up an SLI :
  • RTX 2080 Ti Founders Edition
  • RTX 2080 Ti KFA2 OC White
(both under water cooling)

1) Can you confirm to me that the SLI will work? (I think so after having searched the internet a lot)

2) How is the overclock done? Does the card synchronize their frequencies? Is it possible to overclock the cards independently? If it is preferable for them to be at the same frequencies, what can I do with MSI Afterburner, I overclock my Founders and the KFA2 will automatically apply the same frequencies when launching a game? or not ?

Thanks for your help
 

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Like a fox!
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Hi all,

I would like to set up an SLI :
  • RTX 2080 Ti Founders Edition
  • RTX 2080 Ti KFA2 OC White
(both under water cooling)

1) Can you confirm to me that the SLI will work? (I think so after having searched the internet a lot)

2) How is the overclock done? Does the card synchronize their frequencies? Is it possible to overclock the cards independently? If it is preferable for them to be at the same frequencies, what can I do with MSI Afterburner, I overclock my Founders and the KFA2 will automatically apply the same frequencies when launching a game? or not ?

Thanks for your help
Cards do not sync their frequencies at all. And you end up with bad microstutter if you don't sync it yourself. You'll want to use MSI Afterburner and Control-F to use the curve and set a fixed clock @ fixed voltage to have the best experience.
 

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Cards do not sync their frequencies at all. And you end up with bad microstutter if you don't sync it yourself. You'll want to use MSI Afterburner and Control-F to use the curve and set a fixed clock @ fixed voltage to have the best experience.
Hi,

Thank you for your answer. I am rather new to MSI Afterburner and more generally in GPU overclock. You indicate that the cards must have identical frequencies.

So how does NVIDIA Boost work with SLI? because it will vary the frequency and depend on the temperature and the power limit.
Besides, how should I adjust my Power Limit? which is different between the two card. In addition, the value is indicated in% and not in Watt.
 
Joined
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1,147 Posts
Hi all,

I would like to set up an SLI :
  • RTX 2080 Ti Founders Edition
  • RTX 2080 Ti KFA2 OC White
(both under water cooling)

1) Can you confirm to me that the SLI will work? (I think so after having searched the internet a lot)

2) How is the overclock done? Does the card synchronize their frequencies? Is it possible to overclock the cards independently? If it is preferable for them to be at the same frequencies, what can I do with MSI Afterburner, I overclock my Founders and the KFA2 will automatically apply the same frequencies when launching a game? or not ?

Thanks for your help
Whether the SLI will work depends only on whether you can connect cards with a bridge, and whether your motherboard supports it and you have at least 8 lanes per card. NVLink bridges are not flexible, so cards have to be the exact same width.

Overclock is done the same as with single card, only you need to create two curves. Then choosing a profile in MSI Afterburner is going to apply the corresponding curves to both cards. There is a frequency sync option but it is buggy.

The are two important things with overclocking SLI to keep in mind though.

First is that gain from OC in SLI behaves differently than with single card and you gain much less. For example for the same OC on the single card I get 15% gain but in SLI only around 6%. I've seen that on both 2080 Ti SLI and 1080 SLI. There can be exceptions like Witcher 3 that scale perfectly with memory clock, there I get 11%, but still less than 18% on single card. So all in all core clock in SLI doesn't do that much.

You also really don't want to be hitting power/thermal limit or introduce any other variables like that. The trick with SLI is to tune the cards to be as "calm" as possible, so absolutely no hitting power limit, no crazy OC, etc. So max out your memory clock and aim for some middling core OC like 2025 MHz at lower voltages. You should also flash both cards to 380W BIOS, 320 on FE is going to be a problem.
 

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Whether the SLI will work depends only on whether you can connect cards with a bridge, and whether your motherboard supports it and you have at least 8 lanes per card. NVLink bridges are not flexible, so cards have to be the exact same width.

Overclock is done the same as with single card, only you need to create two curves. Then choosing a profile in MSI Afterburner is going to apply the corresponding curves to both cards. There is a frequency sync option but it is buggy.

The are two important things with overclocking SLI to keep in mind though.

First is that gain from OC in SLI behaves differently than with single card and you gain much less. For example for the same OC on the single card I get 15% gain but in SLI only around 6%. I've seen that on both 2080 Ti SLI and 1080 SLI. There can be exceptions like Witcher 3 that scale perfectly with memory clock, there I get 11%, but still less than 18% on single card. So all in all core clock in SLI doesn't do that much.

You also really don't want to be hitting power/thermal limit or introduce any other variables like that. The trick with SLI is to tune the cards to be as "calm" as possible, so absolutely no hitting power limit, no crazy OC, etc. So max out your memory clock and aim for some middling core OC like 2025 MHz at lower voltages. You should also flash both cards to 380W BIOS, 320 on FE is going to be a problem.
Thank you for the clarification :)

To be honest, I don't have the KFA2 yet, it's a used board (with the same PCB) that I spotted. I am desperately looking for a second Founders Edition ....... If anyone has one for sale I would like to take it!

On the other hand I will not be able to flash my FE with the 380W BIOS because the version of the XUSB-FW is not identical.
 

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Like a fox!
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Hi,

Thank you for your answer. I am rather new to MSI Afterburner and more generally in GPU overclock. You indicate that the cards must have identical frequencies.

So how does NVIDIA Boost work with SLI? because it will vary the frequency and depend on the temperature and the power limit.
Besides, how should I adjust my Power Limit? which is different between the two card. In addition, the value is indicated in% and not in Watt.
This is part of why everyone claims "SLI IS DEAD" on the internet. It's virtually impossible to synchronize the clocks on both cards with the 2000 series and 3000 series due to how nvidia boost works. I've heard people in here talking about some sort of XOC bios for the 2000 series in this thread? If that's possible and it can run with no power limit then you might be able to get the clocks sync'd if you put that bios on both cards and if you're using full-cover water blocks on both and if you have a water loop to keep both cards < 60c and then set the same clocks via two curves it MIGHT work. The GTX 1080 Ti is the last Nvidia card I'm aware of where we can lock in a fixed clock for multiple cards in SLI with an unlocked XOC bios and afterburner. And if you don't sync the clocks then you get microstutter and it's not a fun experience. On top of that SLI support from games is literally zero. Almost all new games released within the past 2 years have no SLI support at all. Nvidia already confirmed they will be dropping SLI support via drivers some time this year too. It was supposed to happen this spring but it can happen any time now. In the future the only way to get SLI / Dual cards working will be in DirectX12 / Vulkan games and via mGPU which is programmer dependent (The game developers have to code it in to their games to support it. If they don't, the game won't use multiple cards at all).
 
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This is part of why everyone claims "SLI IS DEAD" on the internet. It's virtually impossible to synchronize the clocks on both cards with the 2000 series and 3000 series due to how nvidia boost works. I've heard people in here talking about some sort of XOC bios for the 2000 series in this thread? If that's possible and it can run with no power limit then you might be able to get the clocks sync'd if you put that bios on both cards and if you're using full-cover water blocks on both and if you have a water loop to keep both cards < 60c and then set the same clocks via two curves it MIGHT work. The GTX 1080 Ti is the last Nvidia card I'm aware of where we can lock in a fixed clock for multiple cards in SLI with an unlocked XOC bios and afterburner. And if you don't sync the clocks then you get microstutter and it's not a fun experience.
Clocks do synchronize as they always did. The only situation where they don't is explicit mGPU in games SOTTR for example, but this is not SLI. A lot bad things can be said about viability of SLI and it will really die once 4000 series launches and single GPU will match the best SLI you can make, there is really no need to make up additional imaginary problems like clock synchronization to make it look worse, it is now entering it's last year of life anyway.
 
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anyone know if its possible to flash the evga hydrocopper bios onto a xc ultra? I have the hydrocopper block and its cool as a cucumber but im leery on trying the bios as its non-reference.

there was a mod on the evga forums who mentioned he used the ftw3 bios on his xc without problems (which was also a reference > non-reference flash) but I dont want to take a single piece of anecdotal evidence to heart without some reinforcement :p
 

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anyone know if its possible to flash the evga hydrocopper bios onto a xc ultra? I have the hydrocopper block and its cool as a cucumber but im leery on trying the bios as its non-reference.

there was a mod on the evga forums who mentioned he used the ftw3 bios on his xc without problems (which was also a reference > non-reference flash) but I dont want to take a single piece of anecdotal evidence to heart without some reinforcement :p
Why not just use the Galax/KFA2 380W BIOS for reference PCBs from page one?

Best regards,
Medizinmann
 

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Like a fox!
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anyone know if its possible to flash the evga hydrocopper bios onto a xc ultra? I have the hydrocopper block and its cool as a cucumber but im leery on trying the bios as its non-reference.

there was a mod on the evga forums who mentioned he used the ftw3 bios on his xc without problems (which was also a reference > non-reference flash) but I dont want to take a single piece of anecdotal evidence to heart without some reinforcement :p
We're on page 643 of this thread and there have been literally thousands of different posts in this thread alone in the past about people flashing all sorts of different bios's in to stock and AIB 2080 Ti's. I think we have a little more data than just one person by now.
 

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We're on page 643 of this thread and there have been literally thousands of different posts in this thread alone in the past about people flashing all sorts of different bios's in to stock and AIB 2080 Ti's. I think we have a little more data than just one person by now.
so youre suggesting what? I go through 643 pages? Or you simply dont know the answer?

I flashed the galax 380w bios many moons ago and have used it ever since. However that is from a 16 power phase reference board. the ftw3/hydrocopper are custom/19phase. Not interested in making a paperweight.
 

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Why not just use the Galax/KFA2 380W BIOS for reference PCBs from page one?

Best regards,
Medizinmann
Ah, missed your post. I am using that one. However I'm having some issues with LEDsync and figured on the super slight chance using an evga bios helps I might as well try over 7 watts. Plus I feel better (marginally to be fair) to have an evga bios sitting on an evga card :p
 

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well - i yolo'd it. fortunately all is well and i hadnt even looked but the boost clock is much higher on the hydrocopper version than the galax so it was a worthwhile change anyways irrespective of the few watt power target loss (i assume).

also fixed my obnoxious ledsync issue so theres that. I'm gonna call it a win. (outside of paying abhorrent prices for a 2080ti only to have it shat on by a 3080, but thats a rant for another day) The bright side is i couldnt get one even if i wanted to at the moment ;p
 
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