Question : centos4.6 use resource less than 5.1 ?

centos4.6 use resource less than 5.1 ?
apache 1.3 use resource less than 2.2 ?
php 4.x use resource less than 5.x ?
perl 5 use resource less than 6 ?

I have VPS 512MB ram. Please recommend.  I don't care about securities and features.

Answer : centos4.6 use resource less than 5.1 ?

apache2 has single-proces multithreaded mode that resembles 1.3 had on windoze and it is highly efficient when running php but has drawbacks running cgi.
Kernel 2.6 has support for offloading TCP/IP processing onto netcard, SATA queeuing support and some other advantages, though it by default requires a bit more RAM.
Perl6 runtime is smaller though more libraries are included and disk footprint doubles. Ame with Java.
So I suggest using latest stable version for generic requirements. CentOS or Fedora is good if you have to use commercial rpm packages. For all other uses Debian or Ubuntu suits fine. I've had better experiences with SuSE and commercial packages. For example OpenSUSE or Mandriva has more solid unpaid support than RHEL or CentOS.