MarcoB congratulations on your Intel i9 build times! great news to hear.
I do make -j4 buildworld and buildkernel on Raspberry Pi 4B with 8 gigs, with USB 3.0 to NVMe (Ugreen case 1000Mbyte per second) or USB 3.0 to 2.5" SATA SSD (500Mbyte per second)
World takes about 16+ hours; Kernel takes about 5 hours. Yes, slow but gets the job done!
--- kyua.debug ---
objcopy --only-keep-debug kyua.full kyua.debug
--- kyua ---
objcopy --strip-debug --add-gnu-debuglink=kyua.debug kyua.full kyua
4524.20 real 14851.66 user 2066.14 sys
--- buildworld_epilogue ---
--------------------------------------------------------------
>>> World build completed on Tue Jan 16 20:28:29 PST 2024
>>> World built in 57221 seconds, ncpu: 4, make -j4
-------------------------------------------------------------- 57221/3600=15.9 hours
===> usb/g_keyboard (all)
--- all_subdir_usb/g_modem ---
===> usb/g_modem (all)
--- all_subdir_usb/g_mouse ---
===> usb/g_mouse (all)
24.62 real 42.33 user 34.18 sys
--------------------------------------------------------------
>>> Kernel build for GENERIC-VCHIQ completed on Tue Jan 16 20:50:49 PST 2024
--------------------------------------------------------------
>>> Kernel(s) GENERIC-VCHIQ built in 26 seconds, ncpu: 4, make -j4
--------------------------------------------------------------
27.62 real 42.96 user 35.70 sys
Well it was only one file to recompile. So very Fast on Raspberry Pi 4B
time make -j4 buildworld -DNO_CLEAN
time make -j4 buildkernel KERNCONF=GENERIC-VCHIQ -DNO_CLEAN
The important fact is, that FreeBSD allows access to tools and sources to allow a meager system to rebuild world and kernel. So where ever you live in the world, you have access to FreeBSD open source software with BSD license ( ha ha is that what FOSS means?) Instructions to build Kernel
https://ghostbsd-arm64.blogspot.com/2022/09/freebsd-140-compiling-kernel-for.html search word "compile" to find other entries