DX12 VRAM stacking. Is anyone actually experiencing it?

[GObonzo]

Over the last couple years I have read and heard quite a bit about DX12 and what improvements and new features it may be bringing. Two I am really interested in are the cross manufacturer compatibility, AMD & Nvidia working in tandem, and the VRAM stacking option.

Has anyone running multiple cards in Windows 10 RTM experienced either of the these two "phenomena"?

 

[rgd1101]

There isn't a game support DirectX 12 yet.

 

[ESPclipse]

VRAM stacking is meant to be implemented with DX12. AMD has already done it with the Mantle API, so it's pretty much a shoe-in for AMD cards at least. Cross-manufacturer support will be supported, but will not experience scaling of matched cards, no doubt.

 

[GObonzo]

DX12 is already implemented in Windows 10. Hence why I ask if anyone is experiencing the stacking or cross GPU results. Not asking if you also believe it will implemented, but if you are experiencing it.

I haven't ever seen a report of a Mantle supported game allowing VRAM stacking by turning on Mantle in game settings. And all the arguments about GPUs and explanations about VRAM mirroring I have never read anyone claiming while using a Mantle supported game that their VRAM was "stacked".

 

[GObonzo]

There isn't a game support DirectX 12 yet.

that should have nothing to do with how the system's API reads your GPU(s). even if what you said was relevant, 3DMark's API tests should show your memory stacked.
but even in Windows 10, using the correct GPU drivers, VRAM should still show as stacked or mirrored and the cross manufacturer cards should both still show in system information instead of just the one you've chosen through BIOS. if it is being implemented yet.

 

[Jezzyjz]

no programs or games have been written to take advantage of these features you speak of in dx12. stacking WILL NOT occur unless the game has been written that way!!! listen to what I'm saying here OK, none of the older games/software will allow stacking of your cards vram, by old I mean gta 5, witcher 3 etc. the only way they would allow stacking is if the developers were to rewrite these games to stack vram. now look at this logically, THAT IS NOT going to happen OK. however developers will no doubt release programs and games in the future to allow these features in dx12, but that's solely dependant on the developers, NOT THE CARDS. also, to take advantage of all the features of dx12 you will need a nvidia 900 series card. anyone saying anything different to this are stupid or talking bull.

 

[ESPclipse]

Mantle does already support VRAM stacking, but yes, it is up to the developer to implement such ability.

 

[jerdle]

OP this realm isn't about dx12, so much as it is about drivers and developers.

In order for vram to stack, you have to use split frame rendering in crossfire or sli. This is in comparison to alternate frame rendering that multi gpu setups use now.

In AFR, each gpu renders every other frame.
In SFR, each gpu renders half of every frame.

A long time ago, AFR was adopted because it spat out higher frames per second. Higher fps sells more cards.

Well, now its about moving back to SFR - because while it may have lower fps, it allows for the vram in each additional card to stack on top of the first one, instead of all being a copy of the data in the first one's vram. And it delivers a much smoother delivery of frames.

The only game I can think of that uses SFR is Civilization V, a mantle game.

 

[Dartmaster]

OP this realm isn't about dx12, so much as it is about drivers and developers.

In order for vram to stack, you have to use split frame rendering in crossfire or sli. This is in comparison to alternate frame rendering that multi gpu setups use now.

In AFR, each gpu renders every other frame.
In SFR, each gpu renders half of every frame.

A long time ago, AFR was adopted because it spat out higher frames per second. Higher fps sells more cards.

Well, now its about moving back to SFR - because while it may have lower fps, it allows for the vram in each additional card to stack on top of the first one, instead of all being a copy of the data in the first one's vram. And it delivers a much smoother delivery of frames.

The only game I can think of that uses SFR is Civilization V, a mantle game.

It would seem The witcher 3 also stacks vram. I was trying to get some clarification in this thread http:// but I'll post a vid and some screens later when I get home