Nothing much. Use like normal x86 besides:
- Kernel set to Your CPU in Processor Setttings (generic x86_64 is good for all configurations).
- Accept keyword for "Beta"-like packages is ~amd64 not ~x86
- You don't have to set MMX flag, but set SSE, SSE2 and if Your CPU have it - SSE3 this will optimize floating point operations.
- Enable SMP (symmetric Multiprocessing) where available - by flags.
- If it's multicore (I have Intel on my LAP so don't know about Your CPU) set MAKEOPTS to cores count+1.
- If it's multicore try to enable threads flag - this boosts performance even on single core cpus, but on multicore will make much difference.
- Chceck by eselect what profile of portage you have set as default. If is not try setting some with Amd64 on path.
- When GCC upgrade check if "multilib" is set - this will enable You to link with 32-bit libs and 64-bit (as standard).
- In kernel set ciphers and algorithms (like MD5, SHA etc) to amd64 version.

I think that's it. Everything elese should be fine.

2010/12/8 Dale <rdalek1967@gmail.com>

Hi,

First post here. I'm usually on gentoo user. I'm in the process of building a new system which will be 64 bit. I am looking for advice. I would like people to post things that I might run into that one wouldn't expect and some things that are different from x86. I was looking at something on my old rig and noticed the USE flag smp. I didn't know about that until I ran up on it. I learned something by pure dumb luck.

I'm a long time Gentoo user. Installed it at the early stages of 1.4. I also use KDE and have fluxbox installed as a backup. The processor is a AMD Phenom II X4 955 @3.2Ghz. It will start out with one 4Gb stick of ram. I plan to expand that later.

What are some things that I should watch for and enable that isn't so obvious for someone new to 64 bit?

Thanks.

Dale

:-) :-)

--
Mateusz Mierzwiñski

Bluebox Software http://www.blueboxsoft.pl/mateusz-mierzwinski