Both Mantle and DX12 can combine video memory
Robert Hallock (Head of Global Technical Marketing at AMD) shared something interesting on Twitter earlier on. You guys know that when your have a GPU graphics card combo with dual-GPUs that the memory is split up per GPU right ?
Thus an 8GB graphics card is really 2x4GB. As it stands right now, this will be different when DirectX 12 comes into play and apparently already is with Mantle. Basically he states that two GPUs finally will be acting as ‘one big’ GPU. Here's his complete quote:
Mantle is the first graphics API to transcend this behavior and allow that much-needed explicit control. For example, you could do split-frame rendering with each GPU ad its respective framebuffer handling 1/2 of the screen. In this way, the GPUs have extremely minimal information, allowing both GPUs to effectively behave as a single large/faster GPU with a correspondingly large pool of memory.
Ultimately the point is that gamers believe that two 4GB cards can’t possibly give you the 8GB of useful memory. That may have been true for the last 25 years of PC gaming, but thats not true with Mantle and its not true with the low overhead APIs that follow in Mantle’s footsteps. – @Thracks (Robert Hallock, AMD)
There is a catch though, this is not done automatically, the new APIs allow memory stacking but game developers will need to specifically optimize games as such. An interesting statement.
Keep in mind though, this is a marketing rep talking ...
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Last Civilization: Beyond Earth use allready SFR with Mantle..
http://www.anandtech.com/show/8643/civilization-beyond-earth-crossfire-with-mantle-sfr-not-actually-broken
Thankfully, AFR is not the only approach to multi-GPU. Mantle empowers game developers with full control of a multi-GPU array and the ability to create or implement unique MGPU solutions that fit the needs of the game engine. In Civilization: Beyond Earth, Firaxis designed a "split-frame rendering" (SFR) subsystem. SFR divides each frame of a scene into proportional sections, and assigns a rendering slice to each GPU in AMD CrossFire configuration. The "master" GPU quickly receives the work of each GPU and composites the final scene for the user to see on his or her monitor.
/QUOTE]
Ofc, in the case of SFR ( split frame render ), developpers need to put more time and work with it, compared of fix some few problem with AFR ( texture / light flashing, scaling )
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Yeah I hear you....... Does sound a bit fishy as both GFX card companies have truly addressed their concerns on stacked/unified RAM architecture and how they plan on introducing it to the public. All in due time I suppose.
Makes me feel like my kids on Christmas, or something........waiting ever so patiently to find out what the companies are going to give us.
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Seeing that even if I added a second 970 to my rig, I would still be under the power restraints that is the Mac Pro and the silly power connectors that comes with it. I would add a second one no problem if developers did use this API.
I would have more than 4gb of memory then!(Joke)
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Quad TITAN's standing by to stack some memory.....! Just hope they don't pull one over on us about how this is just for the newest brands and no backward compatibility with us guys with the older hardware.
Please do not be another marketing rep blowing smoke attempting to rattle the cages of us hardware freaks that are out there.
Soon as the games hit 6-8gb of vram, your quad titan's, even if they scaled at 100% full speed, your cards, all 4 of them, will be on their knees, 8gb vram???, forget it.
maybe 6gb vram and settings,etc but at full 8gb vram? 100% even with 4 980 gtx's oc'ed, will be on their knees.
5-6gb sounds good, over that, our cards ain't fast enough to do something like that yet and maintain very high fps at the same time.
LOL, and LG is talking about 8k resolution this year? PLEASE!!
Games wont move period at that resolution, as of now no, OLD!! games perhaps, Today's games? FORGET IT...
If people own 4k, Try maxing out with dsr, should give you a hint how fast it will move, lol.
5gb sounds perfect.
Shoot, playing farcry4 @ slightly over 2560X1600 res(DSR), + maxed out settings + nvidia inspector 2xmsaa + 2xSGSSAA, sucker is moving like 17+fps to 20+ fps, seems to moving alright, looks great, lol.
I cant imagine running 8k with farcry4 with everything maxed out @ 60fps, holy good god moly, thats NEVER going to happen for a LONG LONG TIME.
As of the Mantle+DX12:
All I got to say is this, its about time, how many years later and still haven't found out a way to stack the vram? I knew it was just a matter of time, good god about time, I wonder when this will be coming out in full force? I don't expect anytime soon.
Matter of time before Nvidia comes up with there's, lol.
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I still will not go multi gpu even if this is true, the issues with games not supporting sli or doing it poorly are too great imo. I am biased as I had a nightmare 9 months with a 5970 back in 09, poor ati drivers + terrible xfire support in the games I was playing = RMA and lots of rage