Combine and Ati and an Nvidia GPU?

[MiRai]

For me it was less about combining an AMD and Nvidia GPU and more about DX12 being better than current DX at utilizing more of multi GPUs, and all of the ram. IF it can utilize all the ram of two different GPUs, then it can do it with with two of the same?

Right, DX12 is supposedly going to allow VRAM to be added together, but only if the game company/publisher/devs want to support it. It's not just going to be a switch that they're going to have to turn on, and they're going to have to designate assets in their game to be rendered on a particular GPU. So, the way that I understand it is that GPU1 would render things like trees, foliage, and shadows, while GPU2 rendered character models, particle effects, etc. But what happens when you add a third GPU? Or a fourth? What happens when one GPU becomes overloaded with whatever it's assigned to? Does it offload that to the other GPU(s) or does it tank the frame rate?

Honestly, it sounds like it could easily end up being a nightmare to implement such a system into a game like World of Warcraft. Blizzard would not only have to upgrade WoW's engine to support DX12, which is likely years away, they'd also (assumingly) have to directly support SLI in their game -- something they haven't done ever -- but who knows, maybe it's not as difficult as I see it in my non-programmer mind.

Don't get me wrong, I'm looking forward to seeing the next version of DirectX in action, but it sorta seems like Microsoft went into panic mode when AMD released Mantle and it began to gain traction, and now everything new we've been hearing over the past few weeks about DX12 are these crazy in-a-perfect-fantasy-world features that don't really matter all that much. All I want is better performance, more efficiency, and fancier graphical features, and that's it.

In other words..it sounds like DX12 will be an improvement to how multi GPUs work. Im mean right now if you have two GPUs with 3G ram each in SLI or Crossfire, you still only have 3 total right?

Correct, but the 900 series GPUs brought 4GB, and the generation after that (later this year, hopefully) is going to bring at least 4GB, if not more (not counting any Titan-like GPUs) -- GPU VRAM is only going to keep going up.