I'm confused too, lol. The problem is it's all very new and people haven't really settled on standardized naming. At the end of the day they are all MCMs(https

I'm confused too, lol. The problem is it's all very new and people haven't really settled on standardized naming. At the end of the day they are all MCMs(https://en.wikipedia.org/wiki/Multi-chip_module https://en.wikipedia.org/wiki/Multi-chip_module). Previously, RAM, CPU, and GPU were all connected by the motherboard with copper(or similar) based wires. Because the wires can't overlap on the motherboard, there could only be X wires connecting the CPU/GPU to the RAM. To replace the RAM, either disconnect it from the slot or de-solder all X wires if needed, then replace the RAM chips. Based on what I've read the M1 is a single MCM using a silicon-interconnect fabric, where the RAM and CPU/GPU are to each other's left and right[1]. This reduces the length of the wires a lot, which is a lot more efficient and improves performance. However, it still means you can only have X "wires" going from the CPU to the memory because the "wires" can't overlap. In theory (with very expensive equipment), you could "disconnect" all X "wires" and "pick up" the RAM chips and swap them for new ones. A 3D chiplet[2] has the components stacked on top of each other i.e. the CPU/GPU is on top of the RAM, i.e. the RAM is below the CPU/GPU. Technically you could keep the legacy number of "wires", i.e. X "wires" between the CPU and memory, however, because the "wires" now go up and down (rather than left and right) they can never overlap and you can now increase the bandwidth by having X100 or X1000 more "wires" between the CPU/GPU and RAM. While, theoretically you could still "disconnect" the up and down "wires", because there are sooo many more "wires" between the stacked chips everything gets more difficult, and replacing them gets even even more expensive. At which point, from my perspective, basically puts them in the category of "single integrated circuit" or "monolithic integrated circuit" (which is probably a better description than my previous use of "single component"). [1] Pic from Apple: https://www.apple.com/newsroom/images/product/mac/standard/Apple_new-m1-chip_11102020_big.jpg.large_2x.jpg https://www.apple.com/newsroom/images/product/mac/standard/A... [2] https://wccftech.com/amd-discloses-multi-layer-chip-design-era-starting-with-zen-3-with-3d-stacked-v-cache-technology/ https://wccftech.com/amd-discloses-multi-layer-chip-design-e...