How to enable SLI for DX11 or DX12 client?

SLI and Crossfire isn't enabled in DX12 currently.

In DX12 Multi GPU is a new beast.  It's not SLI/Crossfire anymore in the sense you are used to it.

Read this great article that came out on the topic, specifically on Ashes:

http://www.anandtech.com/show/9740/directx-12-geforce-plus-radeon-mgpu-preview

Any idea about the DX11 client?

Thanks for the article, can't wait!

How do I Test AFR GPU? I have 7 GPUS, NVidia and AMD, Id like to test them mixed.

seems they are to busy showing off to supply basic support for sli and crossfire.

At this time SLI/Crossfire is not available.

The build in the article is not available yet to current players.

I play at 1440p with pretty much a top-end rig with the weakest link being my 2x 980GTXs.  30 FPS is NOT playable, period.  I grew up to 30FPS and it is a HUGE difference.  Optimize the game or enable SLI support, I will be waiting with many others (check actual steam stats gametime for this game).

just a reminder, we are still waiting

I'm not sure if people realize this but on DirectX 11, SLI/Crossfire is a driver specific feature.  There's nothing we can do to "support" it or not. 

any updates on a DX12 multi GPU build then?

Alpha 4: November 2015 <---YOU ARE HERE
Begin adding Global Abilities, Orbital Structures, Ice Worlds, Stacked Multi-GPU support,
Benchmark II, first general polish pass

which did not happen

Beta 2: February 2016 (0.95)
Multi-GPU support Added.
Multiplayer: Ranked games begins.
Spectator Mode added.

so what is the difference between "Stacked Multi-GPU support" and "Multi-GPU support Added"

Nope, I didn't realize this.  So can you help me understand, are you saying that AMD has to enable crossfire support for your game in the driver?  I honestly don't understand but as I've just set up two r9 290x's would like to know how this works.

DX11 is quite opaque I believe so the game developer can do the best they can and no doubt try and follow certain guidelines but Nvidia and AMD often have to do a fair bit to get games running as well as possible on their hardware. Some game developers really do shoddy work though which leave Nvidia or AMD with problems sometimes (often?).

As SLI/CF is handled at the driver level and as dx11 is opaque that means AMD or Nvidia have to do it. However games can be developed with or without SLI in mind and if they aren't then they may not be able to support SLI/CF, as is with the case with the latest Batman game I believe.

DX12 allows the game developer to get deeper into the nitty gritty ("closer to the metal" they call it) so they should be able to support multiple GPUs independently from the driver/GPU maker. I only read it very quickly (so may be wrong!) but reading the recent tomshardware article about multi-GPU support it sounds like at the moment Ashes will in essence be running similar to dx11 versions, with duplicating the work on the two GPUs and alternating frames between them and are not yet pooling the memory of the two graphics cards. Having said that, it works differently under the bonnet so is now independent from drivers.

Hmm, I could be wrong in all that and wrote it poorly, regardless by release you will have the choice of CF or dx12 for your full multi-GPU support so you'll be good to go

Thanks Ticktoc.  I had an extra 290x so it's in my rig, but so far the promise of multi-gpu gaming is non-existant.

Where is the list of crossfire supported games?  Why in the world wouldn't AMD publish this?  I found a list from 2011 that some gamer had compiled, and it was woefully short.

Furthermore, I'm having problems in games that don't support crossfire even when I don't try to run them in crossfire (I run them in Windowed/fullscreen to turn it off) so I have to fully disable the 'feature.'  Heroes of the Storm is in this group.

If I'd set out and spent the money to build out a multi-gpu rig, I'd be super pissed right now.  Complete waste of money.

Fortunately one 290 should run Heroes of the Storm fine. 

I don't have AMD, does the new Crimson interface make it easier to turn CR on and off? For some things I think it now supports game by game settings which may be very useful.

A lot of people swear off SLI/CF after they have tried it as it is often not supported or supported late after the release or just more bug prone etc.

The coming years may see a turn around and make multi-GPU a realistic and useful thing to have.

1 - DX12 means the game developer can develop multi GPU support independently from AMD/Nvidia. In theory this should increase the games which come with multi GPU support from day 1. Though unless it is very easy to do I would still only expect it on AAA games or games which are graphically demanding (often the same thing)

2 - DX12 should be able to make more efficient use of the GPUs and by the way it works make them less buggy/prone to problems as well as being better at scaling up with more GPUs.

3 - VR. At the moment* VR produces the image twice (one for each eye). I think the games also need to run at 90fps for a bunch of reasons. So you need some serious horsepower, a need which will only grow as the resolution on the headsets grows. Elite Dangerous, which recommends a GTX 770 on Steam requires a GTX 980 minimum for HTC headset (As well as 16gig of RAM). (http://www.tomshardware.com/news/elite-dangerous-vr-specs-revealed,30696.html)

So over the next couple of years I think multi GPU systems should become more viable/less of a headache and have more things to stretch their legs on.

For Ashes, I would just be patient, it shouldn't be too long hopefully. 2x290x's under DX12 should be very nice indeed.

* I say at the moment as I think I saw some write up of a tech in the works which somehow gets away with only producing the image once. Not sure though. 

Ticktoc - thanks for your reply and I'm sorry I didn't see it until weeks later!

I've taken the second 290x out of my rig - I believe the promise of dual gpu's is far greater than the reality.  There are actually far fewer modern games seeing xfire/sli support each year.  Studios just don't want to spend the additional money to code for it, I guess.

You are correct - VR should certainly see a resurgence - but even then whether it will work in the non-vr version is a big question mark.

No problem

I think I once read that SLI/CF is only used by something like 1-3% of PC gamers - they are a tiny minority really so it is not surprising support is patchy. I hope it does improve though and if DX12 makes it easier to do and less prone to problems then that is great.

If you really want to get rid of that pesky 290x I can supply an address to you and make it disappear forever...free of charge no less!  

Oh Ticktoc, that is so very kind of you!

I'm holding onto the 290x and the 970 until one or the other wins the DirectX 12 wars... I've preferred Nvidia cards for the last 5+ years but at this point AMD may have the edge.

Haha, very wise of you.

I suspect those two cards will exchange blows on a similar footing. You are nicely sorted either way.

Indeed.  Unfortunately SLI/Crossfire on DirectX 11 is a total hack.  It's a marketing gimmick that only works when AMD/Nvidia actually do work on behalf of the game.

By contrast, in DirectX 12, multi GPU is part of the API.   As a result, we don't have to rely on the video card maker to do special work for our game.  We can do it on our own.

Look forward to seeing it in action! Well, 2nd hand action via somewhere like anandtech as I don't have two cards. I like advancements like this regardless.

This is one of the features I'm definitely looking forward to seeing in action with the 2 970 msi. 

My issue is that crossfire was causing issues in HOTS even when I had it turned off for that game!  I mean that is just awful.  I had to disable crossfire for that game and enable it for other games - and really can't name one that showed a difference.

I get the business side of sli/crossfire but find it a shame that there wasn't a better implementation of this cool idea.