Crossfire support?!

Hello I recently upgraded from a single 770 to 2x r9 280x due to a sweet deal I found. I didn’t even think about it but crossfire isn’t supported in windowed programs so when I use unreal engine 4 editor I only get the performance of one gpu. Basically it feels like I haven’t upgraded when I use unreal engine 4 compared to other programs. Is there a way to enable true full screen instead of f11 which doesn’t work? Does the game engine support crossfire in a final build of a game?

UE4 doesn’t support Crossfire or SLI. If it’s something you want your game to support then you’d have to talk to AMD about how you can add support for it yourself.

Also to go along with darth, same goes for SLI.

SLI/Crossfire has been out for going on 10 years now, you would think by now there would be “SLI 2” and would have better “out of the box” experience for indies/customers.

That makes no sense at all, SLI isn’t something that would have versions, it’s like any other graphical feature, if want it then you have to add it in.

Really? then why does every gaming rig maker and all video game bench marks have it as a config? “yeah I know that none of them use unreal based games for benchmarks either”

I mean BF4 supports it as do most modern titles on other modern engines. Why would Epic drop support for this?

They never has SLI support for UE4. There’s probably not that many people who even use it, so it’s not going to be high on their list of things to add support for. And there could be differences between different types of games that would require changes to the settings which might make them adding support a waste of time. Plus they don’t like to work on features that only work on a single brand of GPU–SLI for Nvidia and Crossfire for AMD.

For reference here is a more official reason why SLI and Crossfire are not supported:

Thanks for all the answers. So do you guys plan on supporting it in the future? Could you guys make a workaround for how the deferred rendering techniques rely on the data from the previous frame to render the current frame? In the post you linked you said its not a huge priority which I can understand as a majority don’t use sli or crossfire configs. I’m also a noob to this developing stuff so I don’t know how long it would take for you guys to implement support for crossfire and sli. Just was hoping to get the full amount of performance out of these gpus when using unreal engine 4 editor. Since I lose half my compute power without crossfire. About unreal engine 3 using 3x 580 sli then later on 1x 680 for the Samaritan demo. Did unreal engine 3 support sli/crossfire right off the bat or did it get implemented late in the game? I barely used udk and only on my 770 so I never had this issue with udk since I have only used the 2x 280x with the UE4 editor. One more thing. Can we expect fortnite to support sli and crossfire at launch?


BULLPOOP [EDIT Cuz ugly words :c]


EDIT: And your countter argument about it workking on AMD is abaut as invalid as gameworks AMD performance.

UE4 does not include Gameworks. Nvidia makes that available themselves and it has nothing to do with Epic. UE4 doesn’t include it, because-like I said-they don’t want to include features that won’t work on certain brands of hardware.