Question NVLink - RTX 2080 Ti paired with RTX 2080 (non-Ti)

[mrpeters33]

I know both the 2080 model, and the 2080 Ti model are the only ones to support NVLink, but I haven't been able to find a solid answer on if you can "mix" the two cards.

I recall doing something like this with SLI would cause both cards to operate at the performance level of the lesser card. I am curious if NVLink has enhanced this at all, to instead allow each card to work at their full potential, but in tandem.

I've got a 2080 at my disposal on loan for nothing, so I'd only be out the cost of the NVLink bridge to test performance, but thought I'd check to see if anyone had experience with this yet.

Thanks for any insight you may have!

 

[Barty1884]

For what purpose? Outside of gaming, where you'd be using essentially the "SLI" functionality of NVLink.... I don't see why you couldn't utilize both?

 

[mrpeters33]

For what purpose? Outside of gaming, where you'd be using essentially the "SLI" functionality of NVLink.... I don't see why you couldn't utilize both?

Hi Barty! Thanks for the quick reply.

The purpose would be to have extra horsepower for gaming. Thankfully, the title (iRacing) has had excellent multi GPU support for many generations via SLI.

 

[Barty1884]

I don't think you could utilize them in the SLI/NVLink sense, but I could be wrong.

 

[TJ Hooker]

AFAIK SLI has always required both GPUs to be the same, i.e. you can't combine a Ti with a non-Ti. The requirements for Crossfire were a little more lax.

 

[mrpeters33]

AFAIK SLI has always required both GPUs to be the same, i.e. you can't combine a Ti with a non-Ti. The requirements for Crossfire were a little more lax.

Makes sense, if it is still using SLI underneath NVLink for gaming. Thanks for the advice! Wish I had access to a spare 2080 Ti instead so I could see if the gains are worth it!

 

[theonerm2]

Makes sense, if it is still using SLI underneath NVLink for gaming. Thanks for the advice! Wish I had access to a spare 2080 Ti instead so I could see if the gains are worth it!

Good news. I can run tests for you if you'd like. I have an RTX 2080 ti. The gains are worth it at 4k.

 

[mrpeters33]

Good news. I can run tests for you if you'd like. I have an RTX 2080 ti. The gains are worth it at 4k.

iRacing uses multi-projection for triple screen configurations. I run at a 7680x1440 resolution and have to sacrifice a good bit of effects that I wouldn't on a single screen at any resolution. Thankfully, Nvidia SMP helps, but my framerates are still about 1/3 of what they would be on a 2560x1440 single screen because of 3 views being rendered simultaneously.

If it doubled my frame rate with my current configuration, allowing me to turn on some effects I miss out on, even if it dropped me back to my current framerate (100 to 150 FPS) that would be a win.

I'm just not sure I would see double the gains based on what I've read.

 

[theonerm2]

Unfortunately I don't have that game. I can try project cars though at that resolution and see what it gets.

 

[mrpeters33]

Unfortunately I don't have that game. I can try project cars though at that resolution and see what it gets.

Sure, let me know! See if you can spot my name in the credits

I was a vehicle artist for Project Cars 2

 

[richiestang_78]

I don't see any gain to this, even if the two cards would work wouldn't it only be as fast as the slowest card.

Also for years we've known the gains of SLI is almost none, with only games that are optimized for SLI showing any real gains vs a single more powerful card.

 

[mrpeters33]

I don't see any gain to this, even if the two cards would work wouldn't it only be as fast as the slowest card.

Also for years we've known the gains of SLI is almost none, with only games that are optimized for SLI showing any real gains vs a single more powerful card.

Thanks for your feedback richie. Thankfully, the game in question IS optimized for SLI.

 

[richiestang_78]

Thanks for your feedback richie. Thankfully, the game in question IS optimized for SLI.

You'd have to look, even if the SLI Icon is slapped on it doesn't mean it's optimized, and in many cases games run worse under SLI. The issue is very very very few PCs are multi card setups, so there's not much of incentive for developers to optimize for the technology, since it just adds time and cost to development.

 

[theonerm2]

My RTX 2080 ti gets 120fps at 5K resolution in project cars with mostly medium settings. That's a little higher resolution than what you're running. Also at 8K it gets 50 fps at the same settings and that's triple your resolution. If you want sli you have to get another rtx 2080 though which in turn might not be any better than a single RTX 2080 ti depending on how your game handles sli.

Side note... The game is beautiful at 8k.

 

[mrpeters33]

You'd have to look, even if the SLI Icon is slapped on it doesn't mean it's optimized, and in many cases games run worse under SLI. The issue is very very very few PCs are multi card setups, so there's not much of incentive for developers to optimize for the technology, since it just adds time and cost to development.

iRacing has had SLI support for many years, and their head developer for all things relating to the graphics engine has been optimizing for SLI since late 2016.

2016 Season 4 Release Notes - iRacing.com

Welcome to 2016 Season 4! This season adds the long awaited Circuit des 24 Heures du Mans to the iRacing service! Some extensive updates to the Dynamic Track System have also been added that should increase the realism of heat mapping and make rubber have a bit more of an impact on your race...

www.iracing.com

It's certainly optimized both at the game level, and at the driver levels.

 

[mrpeters33]

My RTX 2080 ti gets 120fps at 5K resolution in project cars with mostly medium settings. That's a little higher resolution than what you're running. Also at 8K it gets 50 fps at the same settings and that's triple your resolution. If you want sli you have to get another rtx 2080 though which in turn might not be any better than a single RTX 2080 ti depending on how your game handles sli.

Side note... The game is beautiful at 8k.

I'd get another 2080 Ti before I'd get another 2080. I own a 2080 Ti. I just have access to a 2080 that won't be utilized anytime soon, so if I could have tossed it in and seen some gains I would have given it a shot.

 

[Barty1884]

I don't see any gain to this, even if the two cards would work wouldn't it only be as fast as the slowest card.

Also for years we've known the gains of SLI is almost none, with only games that are optimized for SLI showing any real gains vs a single more powerful card.

Theoretically, you'd cripple the TI down to 2080 speeds.... but then 2x the 2080.
Of course, it's never that linear, nor should it work like that.

If a game utilized DX12, you could use EMA (explicit multi adapter?).... but adoption was minimal (Ashes, mostly) and in the title mentioned, there's no DX12 support.

 

[theonerm2]

Oh I almost forgot there is a program called different sli.

https://www.techpowerup.com/forums/threads/sli-with-different-cards.158907/

You can sli different cards with it but idk if it has been updated to work with RTX cards.