The latest Ancient computers are able to store massive amounts of data. The Repository of knowledge contained all their knowledge and could process it all in a matter of seconds. They were also a lot smaller than the computer cores of the Asgard and other races. However, it is unknown if it used crystals; it may be a different technology altogether. The databank on Atlantis is of such size that the Atlantis expedition could only store 10% of the relatively small amount of information they had managed to translate with an abundance of portable hard drives and the most advanced compression methods available to them. (SGA: "The Siege, Part 1")