I saw this Anandtech article on
SK Hynix's Q3 lineup including 4GB HBM stacks at 1.6 Gbps & 2 Gbps. What's the consensus for HBM configurations on Vega? Is it generally assumed that both little and big Vega will both use HBM? I've been out of the rumor mill loop.
My gut says that a GP104-competing little Vega would use two stacks of 4GB HBM at roughly 1.6 Gbps. That would yield the same VRAM capacity as GP104 and roughly 25% more bandwidth. AMD GPUs tend to have slightly more bandwidth than equivalent competing Nvidia GPUs, so I think that ratio seems reasonable.
But what about big Vega? If it competes with GP102, then it oughta be roughly 1.5x of GP104-competing little Vega since GP102 is roughly 1.5x of GP104. If little Vega would use two stacks of 4GB HBM, then big Vega oughta use three stacks, right?
However, is a 3-stack configuration even possible? I noticed that an old SK Hynix slide only lists "4 / 2 / 1 Cube" for "Config. / System". Is that the possible number of stacks for a given system?
It would kinda suck if big Vega was forced to use a full-blown 4-stack configuration. In that case, I imagine it would be underclocked similar to the P100.
Also, what HBM parts is Samsung making? I recall an
old article stating that they are in mass production, but I didn't see anything in their catalog. I'm assuming someone has to be producing the HBM for GP100-based stuff.