Question about multiple graphics cards

Hi all. I am completely new to Unreal, but have been involved with 3D modelling (architecture) and rendering for many (many!) years.

I have recently had a new workstation which is great for rendering in VRay as it has dual Xeon CPUs, each with 12/24 cores. It flies! However, the graphics card is a ‘workstation-class’ graphics card which is fine for AutoCAD and 3DSmax (though not necessarily the best for Max, it has to be said). The card is a Quadro 4000. For Unreal, this card is pretty hopeless, so I am thinking about my options.

Ideally, for warranty and Dell support reasons, I would like to keep my Quadro 4000 card in the machine, but also add in an extra card, something like the Nvidia GTX 780 Ti, for use in Unreal (and for VRay RT). Is it possible to have two completely different cards in a Windows 7 machine and instruct which card should be used for which application?

For example, I want AutoCAD to use the Quadro 4000, but I’d like Unreal to use the GTX780Ti.

Anyone had any experience in this? Dell support are hopeless!

I think you would have to get a monitor for each graphics card and maybe that would work. But I would think that the GTX 780 Ti would probably have better performance than the Quadro 4000, even in 3ds Max. So you might consider running the GTX 780 Ti as your main graphics card and including the Quadro as a second one that’s not connected to anything. You can still use the Quadro for improving speed with VrayRT, it just wouldn’t run the viewports.

There’s certainly ways to do this. Personally, I would simply install / fit a Nvidia card into the machine, then disable the Quadro 4000 card via the BIOS. That way, it remains within the machine still, but is simply disabled. If you don’t want to disable it, simply assign the Nivida card as the primary one, with the Quadro 4000 as a secondary.

Interesting ideas guys. Just need to decide on the GFX card. Titan vs 780Ti. Same number of cores, but apparently more RAM on the Titans. That will help VRay RT I guess, but not sure about Unreal.

You can run two different cards at the same time (in Windows 8, and presumably in Windows 7), and tell UE4 to use whichever one. I am currently running an NVidia Titan and a AMD R9 290X in the same machine, then use the r.GraphicsAdapter console variable (Paste into the ConsoleVariables ini file) to control which card to run UE4 on. As for the other programs, they may have configurations to choose which card to run, but if not, you could always use the Quadro as ur main card (So that VRay and such pick it up as the primary and use it). And 780TI/Titan as your secondary and use r.GraphicsAdapter=1 in UE4 to use it.

You don’t need to disable any card, if it’s not being used for running a program, it can just be there and things like VrayRT will pick it up.

So do I need to physically connect my monitor cable to the card I want to use? Or will having the card in the machine perform the ‘calculations’ and output to whichever card is connected?

UE4 allows you to assign a graphics card to run with it, but I don’t think that most programs have that option. I know if you’re using Windows 8 and you’ve got a dedicated graphics card along with the Intel HD GPU that you can right-click on the program and there’s an option to run it from a specific graphics card. But I don’t know whether that works if you have two dedicated graphics cards.

I think Vray allows the same setup.

Just thought I would mention that the 780ti has better performance in games and game creation software for the most part. The Titans are somewhat similar to the quadro cards, as they are great for intense 3d simulation effects, but do not have as good performance in real-time rendered situations (such as games and UE4). I would recommend going with the 780ti, I plan to do the same soon unless the soon to be released 880 is not too much more expensive. Plus when the 800 series comes out, the 780ti will probably get a nice little price drop as well. :slight_smile:

Interesting. The 780ti does seem very reasonable doesn’t it.

Hi - just found this thread which is very interesting to me. I’m running an 2 instances of UE4 on the same machine - they are networked etc. Can i use the command line to send each instance to a different graphics card? I’m using 2 nVidia 980s out of SLI mode (I know UE4 doesn’t use SLI unless nVidia has profiled your game)


I don’t think you can configure two separate instances since they’ll be referencing the same settings. You might be able to do it from two separate installations of a game build though.

Yep this is the only way i could figure out how to do it. Two game installations.

Can anyone confirm that this still works for packaged builds? We are trying this ourselves and no matter what we set r.GraphicsAdapter to it will always use GPU for packaged builds