On 29/08/2023 13:22, Victor Ivanov wrote:
> Hello,
> 
> I will soon be upgrading from a mobile Skylake platform to a desktop
> Ryzen 7000 series and a full re-install is not an option unless all
> else fails. I'm thinking of simply moving the drive and recompile as
> necessary. I don't see why this wouldn't work, but wanted to double
> check with the community just in case.

The only thing I did after upgrading to a different platform (Intel to 
AMD) is *first* switching to sys-kernel/gentoo-kernel-bin on the old 
system, move my storage devices to the new system, and then switch back 
to sys-kernel/gentoo-sources on the new system.

gentoo-kernel-bin is a pre-compiled kernel that serves as a fallback in 
case gentoo-sources won't boot. My CFLAGS are:

   -O2 -pipe -mtune=native -march=native -ftree-vectorize

and didn't need changing. CPU_FLAGS_X86 did of course did need changing 
(with cpuid2cpuflags.)

Usually, critical packages that serve to get you a command-line login 
don't end up using amy "weird" CPU instructions (like AVX512 or 
whatever), but other packages might. So it's best to rebuild @world once 
your new system can boot.