I decided instead on a more conservative route though. Selective recompiles should keep my system from being borked while giving me the maximal experiential benefits e.g. recompiling Firefox; KDE etc. instead of recompiling obscure libraries and dependencies I have no idea about.

I managed to genkernel a post-localmodconfig kernel that has a few other changes from the stock Sabayon one, like the specific optimization for the Pentium4 architectures and selection of a low-latency desktop build. No huge differences I feel on this level yet, if any. I think recompiling the kernel doesn’t really have a huge effect on performance, lest you are talking about drastic recompiles that include some really big patches.

I’m satisfied with my system now, though. Man, I never knew that Linux could be faster.