and they are even kind enough to give you a brand new skulltrail mobo for free!!! they might as well add in a q9770 (or whatever that ones called) and a nice little 8800GT
Those are FB DIMMs which is used in Intel and UltraSparc T2 servers, Kornowski's link says it's just DDR2 which is mainly used in desktops, or opteron servers I suppose but you'd probably want some kind of registered memory when it's that big.
when they give you a skulltrail with a rebate of 659.99 im assuming its ment for servers and such, but that that rate they should be giving you 2 skulltrail rigs with processors