Well here comes an update on my struggle with this ancient piece of kit. I've finally managed to get Debian Stable onto it. after the installer failed completly at putting the bootloader yaboot in place properly despite having made the IBM PReP partition properly and all. i had to exit to shell and then chroot into the target install and run yabootconfig from within and continue the install then get it to work.
So now i've got a nice SSH shell to the box to use. htop shows a nice view of 16 Virtual Cores, 4 Physical cores and 32GB of RAM. Not too bad. Now to get some use out of it for virtualization or something later on.
A screeny of htop on the "beast".
Some load compiling the linux kernel with make -j16 to test.
Oh also if you've noticed that the bottom htop differs in layout from the top one. it's because i re-ordered the CPU Bars to be more evenly distributed left/right instead of all CPU bars on the left and tons of blank space on the right.