I'm right in the middle of developing the
blocks needed for extreme high performance U1 Athlon SMP goodness...
a U1 only gives you 43mm +- from top to bottom...
believe me everything needs to be re-designed, fitting placement, fittings size, retention...
the end result is going to sound something like.....
10 U1 SMP Athlon based units, with a U4 as the cooling station.... neatly stacked, and Clustered in Linux using Mosix load management solutions.