I have heard many good thing about Ubuntu and would like to install on an older computer. My system specs Pentium 4 2.8 GHZ (northwood), 2GB RAM (rambus) and ATI X800 PRO AGP 4X. Would Ubuntu 12.04.3 LTS be the best option or could I go with an older version for better performance? I also heard Unity can slow down older computers big time. Many thanks for any help the community can provide.