Hey, i am relatively new to the whole 'linux thing' i was just wondering... if a software package is compiled on say a 486 machine, does that mean that it is optimised for a 486 machine and thus your missing out on performance if you are using a a new machine?? Or does it make no difference except that it would take a ******* long time to compile ?

Thanks
Snuff

No, gcc is able to make binary to any supported platform from any supported platform. It's called cross-compiling.
So, you can actually compile an optimized code for i686 from a i486, provided you give the right -march flags.

ok, but for instance when you download packages from the slackware site... say x11-6.8.1-i486-2.tgz is it going to run as well on a PIII as it would if i compiled it myself???

Usually, packages compiled for i486 will perform very well on a Pentium, Pentium II, Pentium III, etc...

Compiling a package specifically for one architecture (let's say the Pentium III) only yields minor performance improvements.

Therefore, compiling Apache (for instance), specifically for a Pentium III is only interesting if you have very specific needs (and/or performance problems). Most of the time, these issues can be solved through a better configuration.

This is why, for instance, there isn't (yet) a specific version of Slackware for AMD64 processors: the performance gains do not (yet) justify a recompilation of the entire system.

Hope this helps!