8-way Mac Pro
www.hardmac.com/articles/70
From the page
Saved with the link. Notes from 2007 to 2016 are mostly the page's own words, so this is probably an excerpt.
After dissecting the Mac mini to install a Core 2 Duo inside, we decided to upgrade the CPUs of a Mac Pro. This article aims to provide a step-by-step procedure to exchange both of the original Dual Core 3.0GHz Xeon processors of a Mac Pro with 2 Xeon X53