A, I have pci express in mind when I hear crossfire, I doubt the patent mention or as anything specific to RDNA 4 or RDNA in general, if that the one mentioned:I mean chiplet crossfire ofc. Not 2 physical GPUs
There is an AMD RDNA 4 patent for 3 chiplets in crossfire mode inside same GPU
https://www.freepatentsonline.com/20240193844.pdf
Seem really generic, there is no doubt that all the giants have been looking at this forever, a bit like there was talk that started for the PS5pro a while ago when a 2019 patent from sony : https://www.freepatentsonline.com/y2020/0242723.html, extremelly generic (multi gpu on same die, chiplet, etc... for cloud gaming server, console).
Could be, but I am not sure the patent or its absence mean much, there was leaked design for the cancelled top end RDNA 4, the MI300 do use them in a extreme way (13 chiplets) so they are gaining a lot experiences in that regard, maybe 3d stacking could help, if you put the gpu one over the other that could make a lot of surface for them to speak to each other and reduce latency issue (or a giant cache that cover both that they can share, like they do with HBM memory on the MI300)