[Manuel Calavera]

Ali to na što se odnosio MCM prije je da grafika bude jedan čip, drugi čip nešto drugo - cpu ili ram za grafičku (npr. konzole). Ne postoji gpu (barem consumer proizvod) koja se sastoji od više grafilčkih čipova npr. jedan high end gpu od 2,3,4 čipa od štajaznam 200mm2.

The interview was done with the Senior Vice President of Engineering at AMD Radeon Technologies Group, David Wang. Upon being asked whether the AMD Navi GPUs would use an MCM (Multi-Chip Module) approach, David replied that while they are looking into the MCM approach, they haven’t yet concluded whether that is a viable approach for traditional gaming graphics cards. Following is the quote from PCGamesn:

“We are looking at the MCM type of approach,” says Wang, “but we’ve yet to conclude that this is something that can be used for traditional gaming graphics type of application.” via PCGamesN


“To some extent you’re talking about doing CrossFire on a single package,” says Wang. “The challenge is that unless we make it invisible to the ISVs [independent software vendors] you’re going to see the same sort of reluctance.


“We’re going down that path on the CPU side, and I think on the GPU we’re always looking at new ideas. But the GPU has unique constraints with this type of NUMA [non-uniform memory access] architecture, and how you combine features… The multithreaded CPU is a bit easier to scale the workload. The NUMA is part of the OS support so it’s much easier to handle this multi-die thing relative to the graphics type of workload.”


So, is it possible to make an MCM design invisible to a game developer so they can address it as a single GPU without expensive recoding?


“Anything’s possible…” says Wang.


“That’s gaming” AMD’s Scott Herkelman tells us. “In professional and Instinct workloads multi-GPU is considerably different, we are all in on that side. Even in blockchain applications we are all in on multi-GPU. Gaming on the other hand has to be enabled by the ISVs. And ISVs see it as a tremendous burden.”


Does that mean we might end up seeing diverging GPU architectures for the professional and consumer spaces to enable MCM on one side and not the other?


“Yeah, I can definitely see that,” says Wang, “because of one reason we just talked about, one workload is a lot more scalable, and has different sensitivity on multi-GPU or multi-die communication. Versus the other workload or applications that are much less scalable on that standpoint. So yes, I can definitely see the possibility that architectures will start diverging.”
via PCGamesN

Summary:

But on the gaming graphics card side, David mentions that while the hardware implementation exists to make it work, the software side still needs a lot of updating. It’s quite the same thing as Crossfire or any other multi-GPU interface that exists for gamers. Unless there’s proper software support, you won’t see any gains and with MCM, you are basically trying to make multiple GPUs look like a single GPU. You already know how well things went with SLI and Crossfire which are literally dead and have nill support from game developers. But the issue only exists with gaming industry since, in the server space, multiple GPUs can work together seamlessly with proper performance scaling, unlike Crossfire and SLI. So for Navi, an MCM die seems out of the equation but hopefully, AMD will be able to deliver a working solution in their Radeon cards in future.

With Navi GPUs, AMD is going to stick with the traditional monolithic design that we see on all modern GPUs. Unlike the MCM approach that AMD is taking on their HEDT Threadripper and server EPYC parts, the GPUs are yet to use the full potential of AMD’s Infinity Fabric, something which Raja Koduri wanted to implement on their next-gen Radeon parts. Unfortunately, Raja Koduri left AMD for Intel as the Chief architect of their core and visual computing group and has confirmed to be working on Intel’s first discrete graphics cards aimed at the gaming market for a 2020 release.

Očito je da AMD, Intel i Nvidia rade na tome, pitanje je trenutka kada će doći u mainstream, no zasad još nije "a thing". Također što je drugo MCM gpu nego "SoC razvoj i integracija"

Ako se ne uspije postoji opcija da intel za gaming izbaci monolitsku gpu, a za profesionalnu namjenu gdje to skalira - MCM. Mada glasina govori da je i intelova gaming gpu MCM, a Raja je htio dok je bio u AMD-u da sljedeća generacija radeon gpu bude MCM (mada nejasno dali se pritom misli na Navi ili gen poslije Navija)