Observation. Although it wasn't the case with older versions of #Debian, or perhaps older versions of #XZ, creating archives with xz on Debian, whether thru tar or xz directly, now uses all CPU cores instead of just one like it did before. Just noticed this after doing a fresh install of Debian 13 a while back on my desktop PC.
It's still orders of magnitude slower than #ZST . I haven't done testing in terms of best use cases for XZ, but a real quick test of the Debian 13 Gnome Live CD had the following results on my hardware.
CPU: Ryzen 9 8945HS
RAM: 64 GB DDR5 @ 5,600 MT/s
Storage: Western Digital Black 4 TB M.2 SSD in PCIe Gen 4x4 M.2 slot
Source: 4,102,389,760 bytes
ZST: 4,062,396,293 bytes
XZ: 4,047,963,404
ZST time taken: 2 seconds
XZ time taken: 1 minute 50 seconds
XZ saved an extra 15 MB on a 4.1 GB input.
Marcus Adams