There's no way they'll go multi socket. They can put multiple chips in the same package like AMD has done. Less board space, less latency between cores for cache coherency etc. and they wouldn't need to be limited to "only" 16 cores.i, of course, have no inside knowledge about what sort of glue logic they would, or could, use. We know that there have been several recent introductions of cache coherent high speed interconnects that have been introduced recently. Any one of them could work. I don’t think that the choice is important, as long as it meets their needs.
As for why? It’s all a matter of volume. Apple doesn’t move anywhere near enough high end (greater than 8 core processor) processors to justify a “large” core design that is restricted to those machines. However, to remain relevant in that space, Apple needs to have a decent product. I have previously suggested that Apple is going to offer cloud processing power as a service through extensive cloud integration in a future version of Mac OS. However, if they don’t go that route, they need something.
the premise of these threads is that one A series core is dramatically faster than an x86 core. If we accept that, then it’s reasonable to suppose that fewer Mac Pro products can be better with fewer cores, but that 8 isn’t enough. If that’s a reasonable assumption, then Apple needs more cores, but still wants to make money, and therefore won’t make a chip at a loss for a low volume product. Therefore, a reasonable assumption is that their highest end A series processor will have the ability to be used in a 2p configuration.
16 super fast A series cores should be more computational power than anyone could ever need! /s
I don't think they will go monolithic but I wouldn't totally rule it out. Apple pays Intel and AMD a lot of money for the CPU/GPU going into it now. That leaves Apple with a ton of room to play with as far as designing something special for the Mac Pro / iMac Pro only if they wish, and still have it cost less than what they pay Intel/AMD now.
It all depends on what they are trying to do with it. Do they just want to beat the performance of the current Mac Pro and call it a day, or do they want to make a statement? I don't know, but if they want to make a statement then I wouldn't rule anything out if they get a blank check from above to make that statement heard across the industry.