Wow! Tim_axe, thanks heaps for your insight.
Nihil, thanks for the info on RAM. I'll definitely have a hunt around on EBay for some second hand RAMBUS RAM.
As for the rebuild, this week's a messed up week for me as here in Oz, we've just had a long weekend, and next weekend, my wife, son and I are going away for 3 days.... so I'm probably looking at Wednesday week (about the 12th October) before I can do the rebuild.
Still, might be able to track down some extra RAM before then which would save me having to open the box twice! See? There's good in everything if you only look for it!
Stay tooned....