i haven't built any from total scratch, but i know how. i've modified existing boxes. my computer right now is an ibm intellistation box with a 1TB HDD in a RAID array, 4GB RAM, 2.8Ghz dual-core Intel something or other, nothing too fancy, not a gaming computer, but it's pretty much lightning fast, due to the HDD set up, didn't cost me too much to make happen.