Let’s get started with AMD, and wow, we got a WILD rumor on our hands. On the CPU side, the company is already very familiar with Multi-chip module designs. It started with the first generation of Epyc and threadripper for the first generation of Zen, to the chiplet based Ryzen 3000 and 5000 CPU’s on desktop.
Anyway, it has been rumored that AMD would move that technology to their graphics products too. Many patents have popped up supporting that. In fact, the latest one was filed about a year and a half ago and was just published about a month ago on December 31rst of last year.
The patent describes how multiple GPU chiplets can be connected via a high bandwidth passive crosslink called HBX. It wouldn’t connect the actual fixed-function hardware like the compute units but rather it would unify the cache. Every module has its own set of l1 and L2 cache only accessible by the one chiplet, but the l3 cache is actually shared via the Crosslink we talked about earlier….