Yes, you are correct. RAM is faster than your Hard Disks storage so programs are loaded from your HD to RAM. You maybe have 2 GB ram and 160 GB hard disk space.

I don't know SBS 2003, does anyone know the utility that tells you all of your specs? At any rate in XP you can learn how much ram you have and what cpu you have by right clicking on 'my computer' and selecting properties. May be the same on SBS.