I was planning to run a few 3590's on 1,05A, so this is interesting.
Do you know how mutch 1 heatsink weighs ?
I myself have bought some old Xeon en Itanium server-heatsinks, witch fit a 3590 in a ideal cob holder.
Paid EUR 2,29 for the small ones (left, 450 gr Alu), 2,49 for the big middle...