OK, I cut the socket of my old Abit KG7 and my Asus A7N8X to compare my waterblocks.
The reading "under core" it is the but effective at level of personal tests.
My method has been different, in my drill press I put bit of 4 mm and I slipped the motherboard (with the protected back part) working the groove so that it passed the cable.

The bit even has copper remains. :shrug:
Before that I proved with a thermal probe of the Volcano 9 but the system failure when starting up in two different occasions.
Ketchak.
www.devilmaster.cjb.net