Nvidia working on their own Multi chip GPU designs.

[Mauller]

It appears team green have also been quietly busy in the background, ferreting away at MCM type GPU designs. There is a research paper on the link.

http://research.nvidia.com/publication/2017-06_MCM-GPU:-Multi-Chip-Module-GPUs

MCM-GPU: Multi-Chip-Module GPUs for Continued Performance Scalability

Historically, improvements in GPU-based high performance computing have been tightly coupled to transistor scaling. As Moore's law slows down, and the number of transistors per die no longer grows at historical rates, the performance curve of single monolithic GPUs will ultimately plateau. However, the need for higher performing GPUs continues to exist in many domains. To address this need, in this paper we demonstrate that package-level integration of multiple GPU modules to build larger logical GPUs can enable continuous performance scaling beyond Moore's law. Specifically, we propose partitioning GPUs into easily manufacturable basic GPU Modules (GPMs), and integrating them on package using high bandwidth and power efficient signaling technologies. We lay out the details and evaluate the feasibility of a basic Multi-Chip-Module GPU (MCM-GPU) design. We then propose three architectural optimizations that significantly improve GPM data locality and minimize the sensitivity on inter-GPM bandwidth. Our evaluation shows that the optimized MCM-GPU achieves 22.8% speedup and 5x inter-GPM bandwidth reduction when compared to the basic MCM-GPU architecture. Most importantly, the optimized MCM-GPU design is 45.5% faster than the largest implementable monolithic GPU, and performs within 10% of a hypothetical (and unbuildable) monolithic GPU. Lastly we show that our optimized MCM-GPU is 26.8% faster than an equally equipped Multi-GPU system with the same total number of SMs and DRAM bandwidth.

 

[Mauller]

If it hits mass market, it won't be cheap!

The idea is to reduce manufacturing costs, similar to what AMD has done with EPYC. Although using something like an interposer to connect the dies together.

It is far more profitable to make a smaller chip than it is to make a large monolithic die. As chip size goes down, yields go up as you get more chips per wafer so fewer defects per chip.

 

[Mauller]

To be fair I'm actually quite surprised it's taking so long, after seeing Intel Core 2 Duos hit the scene over a decade ago I was expecting the same to happen to GPUs any day now. That it's taken this long is so perplexing. A GPU with two cores and natural driver/game support is a no-brainer.

From the Paper submitted on the link above, the system will pretty much be invisible to the application. It will just appear as a single monolithic GPU since the cores themselves are just co-processors in essence to a single front-end control chip.