We all know standard parallel DDR memory is reaching physical limits on motherboards, and HBM is far too expensive. The server-market uses CXL Memory Expanders, but no one has adapted this concept for the Desktop market yet.
I just published a draft for the XMM (eXpress Memory Module) Architecture. The core idea is moving the memory controller (OBMC) OFF the CPU die and onto a PCIe/CXL add-in card.
Why it matters:
Motherboards get massively cheaper (no more 150+ parallel impedance-matched traces).
CPU sockets free up ~300+ pins, which can be reallocated for VCORE or more PCIe lanes.
True Modular Unified Memory for Desktop PCs.
We have a photorealistic concept render in the repo of what the card looks like.
Check out the specification and the RFC repository here: https://github.com/Luiguard/XMM-Standard
I'd love to hear some harsh engineering feedback on protocol limits, lane starvation, and bootstrapping!