64GB RAM Under 64-bit Linux?

gary.flake asks: "My group at NECI is in need of a machine that can address 64GB of ram in a single process. This means we need 64-bit addressing. We'd prefer to go with a Linux solution because all of our development is under Linux. We've spec'ed out some reasonable machines (Dell can do 32GB, and Compaq can do 64GB) but they seem to be lacking in that they can only be loaded up with 4 x 800Mhz Itaniums. We would really like to have more processing power (2 Ghz x 4 would be a dream). Does anyone know of any monster Itanium machines that will meet our needs? (Please, no Alphas). Finding such a beast is harder than you'd think."