New IBM Z series is all about the cache!

https://arstechnica.com/gadgets/2021...-architecture/

Basically 8 cores per 7nm chip, 5ghz base clock. Upto 256 cores (32 processors) per system.
Each core has 32MB L2, if it gets full it can move to any other cores' L2 (and becomes L3) but if that isn't possible it can move to any other chip in the system as L4. Overall higher latency is the downside.

Niche and irrelevant to most people but I do have a soft spot for the mainframe, when I last worked on it we were moving from z9s to z10s so it's been a while! I always wanted one of the old chassis to turn into a wardrobe :

https://www.ibm.com/blogs/systems/ib...-ibm-linuxone/