Zen 4 is the name for a CPU microarchitecture designed by AMD, released on September 27, 2022. It is the successor to Zen 3 and uses TSMC's N6 process for I/O dies, N5 process for CCDs, and N4 process for APUs. From Wikipedia
The new lineup refines the Ryzen 7000HX series with minor upgrades, setting the stage for AMD's future Zen 5-powered processors.
