Instead of getting the Titan with the outdated architecture, I opted for a 980, but seeing how the titan has a 12 gigs vram and the 980 has only 4gigs, i got another 980 and hooked them up for a theoretical total of 8.
Question now is:
**1.**Does UE4 utilize both buffers or is it only filling the main one?
**2.**Does dedicating a GPU for PhysX do anything in UE4, or are physics solutions locked to CPU for compatibility reasons?
**3.**Does the second GPU (assuming its dedicated to PhysX) help with rendering when it’s not used at 100%?
**4.**Does it matter where I connect a second monitor? If it does, does this mean that if I connect it to the second 980 that I’d be eliminating SLI, or will both cards help each other with rendering? I’ve done some research and I’m aware of the fact that there’s a main SLI rendering screen that is defined in the control panel, but that’s pretty much all it says.
**5.**And lastly, the main reason I got 2x980’s is because I’m really excited about the FLEX unified solution, and I was really hoping to utilize the new Maxwell architecture with UE4 and dedicate a GPU for the flex solutions, so does anyone know if PhysX will remain locked to CPU?
The editor, as far as I know, has no SLI support whatsoever (for now). So you’d get no benefit and if anything, a performance decrease. That covers questions 1-4.
As for five, I haven’t done much looking into this, but PhysX will highly likely remain locked to the CPU in Unreal because it’s a cross-platform engine, and therefore:
Not all of it’s user have an nVidia GPU
Most of the end users will likely a faster CPU than GPU
However, you could go into source code and get the engine to compile PhysX for GPU instead. You may need to get nVidia Gameworks stuff to do that, though I’m pretty sure the PhysX SDK is free for anyone to get their hands on.
A free account can be registered and you can download the SDK as suggested. While a lot of GameWorks is available to download there are some that require you to contact NVIDIA directly about licensing.
UE4 does not support SLI or GPU PhysX acceleration. For SLI it’s specific for the game requirements so you’d have to work with Nvidia to have an SLI profile made for your game. So right now, your second GPU is useless for UE4.
Also, with SLI you would still only have 4GB of graphics memory, it doesn’t add the memory of both cards together, each card has to load the scene.
Well I feel like I screwed myself…especially if the cards don’t share their buffers. The main reason I got the second one is for 3dsMax though, so I hope at least that can utilize the extra horsepower.
So after reading all this, does this mean FleX will not arrive in UE4? I kind of doubt nVidia will be will be willing to forego exclusivity, it does seem like a lot of work has been done to make it.
3ds Max can’t use SLI either. For iRay or VrayRT it can use as many graphics cards as you have though. But for viewport it only uses one.
Nvidia has a branch of UE4 available with an early version of Flex, they’re going to be offering a number of things from Gameworks integrated to UE4 soon. If you’re a subscriber you can download that branch and compile it.
Just an FYI, Blender will use SLI and the second video card memory and GPU though, but if your using 3Ds Max you are most likely not interested in Blender.
I’ve gotten SLI to work with a nice performance boost over single gpu with nvidia inspector and using the farcry primal profile and then directing that to the \Program Files\Epic Games\UnrealTournament\UE4-Win64-Shipping.exe then in the nvidia control panel set sli rendering mode to force alternate frame rendering 2 otherwise you get flashing artifacts and alternate frame rendering 1 crashes the game alot. I also use adaptive vsync