I want to understand technical details of limitations of maximum memory size a system / processor can support. Below what I was able to find via web search to date Wiki:
Modern 64-bit processors such as designs from ARM, Intel or AMD are typically limited to supporting fewer than 64 bits for RAM addresses. They commonly implement from 40 to 52 physical address bits13 (supporting from 1 TB to 4 PB of RAM). Like previous architectures described here, some of these are designed to support higher limits of RAM addressing as technology improves. In both Intel64 and AMD64, the 52-bit physical address limit is defined in the architecture specifications (4 PB).
Crucial site, understanding-cpu-limitations-with-memory talks about speed only, point to Intel site. But as far as I know, info e.g. i7 tells 32Gb because at time of creating the processor only 16Gb modules was available, meaning it supports 2 modules only (2 modules is my guess now, wiki quote above talks about bits).
I'm only starting to understand technical details how memory works, like ranks. What exactly prevents all modern e.g. Intel processors to claim to being able to address as least 1Tb (per wiki above)?
Is the reason same for ARM in smartphones? E.g. 875:
Max size 24 GB
For ARM I have no experience changing amount of memory as all my devices had SoC, though I recently found ARM should have systems with modules, as web search indicate (e.g. https://www.anandtech.com/show/13635/apacer-launches-32bit-sodimm-for-arm-risc-v-systems).