On 20/08/2024 18:38, Eli Schwartz wrote:
> Your new CPU should support -march=x86-64-v3 but perhaps the old one
> doesn't.
> 
> If you plan to recompile all packages with -march=native immediately
> after you swap anyway, then it doesn't really matter, just use "x86-64"
> for maximum compatibility.

Agreed with this recommendation. Last year I migrated from a dying Intel 
6th gen to a Ryzen 7000 series and went with, IIRC, the most generic 
-march=x86-64 without -mtune.

To save some compile time and electricity I only recompiled @system. 
After migrating the drive to the new system I updated -march accordingly 
and recompiled @system again (just in case, perhaps unnecessarily) 
before ultimately running a full "--emptytree @world" recompile with 
some exceptions from @system. If recompile time and/or energy is not a 
factor, it's probably safer to go with @world in both cases and not bother.

Somebody also suggested then to install "gentoo-kernel-bin" before the 

migration in case there's any compatibility changes and your current 
kernel doesn't boot on the new system.

Ironically, in my case I did have issues with a black screen with my 
kernel, but the gentoo-kernel-bin panic'd straight away. Turns out my 
issue was graphics related and adding "nomodeset" got the screen going 
and I resolved the problem shortly after. So YMMV, but probably doesn't 
hurt to have it as a back up.

Good luck!

- Victor