Interesting, where do you find the size of these dies? I was really curious about how large the Firestorm cores are compared to say Zen3 or Intel cores.
How many cores do you think Apple can realistically add? Can they get up to something like threadpiper. or are we talking more about something along the lines of a 12 core upper limit?
The Zen 3 is interesting. It has a separate IO chip coupled with one or two 8 core processors. The 8 core version has a total die area of about 80 + 125 = 205 sq mm. The 16 core is 285 sq mm.
Intel chips are all over the place depending on core design and number of cores. As an example from the reference above, a 6 core i7-8700K is about 154 sq mm. The i9-9900K is 180 sq mm and the 10 core is 206 sq mm.
How many cores can they add? From the die photograph of the M1, a very rough estimate of area dedicated to the 8 cores and associated cache is maybe 40 percent or 48 sq mm. Compared to the 205 sq mm for the 10 core i9, they could add about 16 more cores. Seems unlikely of course because of all the other things you have to do to support that. It is reasonable though to imagine a 180 to 200 sq mm Mx chip with maybe 16 CPU cores and perhaps a few more GPU cores. Fun.
The fundamental limit to die size is what's known as the reticle size. That's the maximum size of the stepped design that is repeated over the wafer. This is a limitation of the lithography equipment. That limit is around 850 sq mm, but no one builds a high volume chip anywhere close to that big because the yield and therefore the cost would be atrocious. Instead, several repeats of the design are included in the reticle and then that is stepped over the entire wafer.
More interesting is comparing core size, I think. Just spitballing in MS Paint, if we chop off the FP the Zen 3 core plus 1MB L2 is probably ~ 3 sq mm. The M1 seems to be about 2 Firestorm complexes high and 4 wide, so a complex would be 15 sq mm, or ~ 3.75 sq mm for a core plus 3MB L2.
How many cores do you think Apple can realistically add? Can they get up to something like threadpiper. or are we talking more about something along the lines of a 12 core upper limit?