"chip" is ambiguous the way you're using it. The M1 Ultra is two dies in one package. The package is what goes on the motherboard. You can also count the mem

"chip" is ambiguous the way you're using it. The M1 Ultra is two dies in one package. The package is what goes on the motherboard. You can also count the memory modules as packages as well. It's not incorrect to say that M1 Ultra has a bunch of LPDDR5 packages on it as well, each LPDDR5 package may have multiple dies in it as well, or the whole LPDDR5 package may be referred to as a stack ("Ultra has 16 stacks of memory") But depending on context it also wouldn't be incorrect to say the M1 ultra is a package as a chip even if it's got more packages on it. From the context of the motherboard maker, the CPU BGA unit is the "package". Anyway no, Ultra isn't a monolithic die in the sense you're meaning, it's two dies that are joined, Apple just uses a ridiculously fat pipe to do it (far beyond what AMD is using for Ryzen) such that it basically appears to be a single die. The same is true for AMD, Rome/Milan are notionally NUMA - running in NPS4 mode can squeeze some extra performance in extreme situations if applications are aware of it, and there's some weird oddities caused by memory locality in "unbalanced" configurations where each quadrant doesn't have the same amount of channels. It just doesn't feel like it because AMD has done a very good job hiding it. However you're also right that we haven't reached the end of monolithic chips either. Splitting a chip into modules imposes a power penalty for data movement, it's much more expensive to move data off-chiplet than on-chiplet, and that imposes a limit on how finely you can split your chiplets (doing let's say 64 tiny chiplets on a package would use a huge amount of power moving data around, since everything is off-chip). There are various technologies like copper-copper bonding and EMIB that will hopefully lower that power cost in the future, but it's there. And even AMD uses monolithic chips for their laptop parts, because of that. If any cores are running, the IO die has to be powered up, running its memory and infinity fabric links, and at least one CCD has to be powered up, even if it's just to run "hello world". This seems to be around 15-20W, which is significant in the context of a home or office PC. It's worth noting that Ryzen is not really a desktop-first architecture. It's server-first, and AMD has found a clever way to pump their volumes by using it for enthusiast hardware. Servers don't generally run 100% idle, they are loaded or they are turned off entirely and rebooted when needed. If you can't stand the extra 20W at idle, AMD would probably tell you to buy an APU instead.