mac pro cpu upgrage

Hi all sometime ago, I bought a MP 5.1 really, really cheaper (round 350 euros). It has the following configuration right now: - 1 x 2,8 GHz Quad-Core Intel Xeon - 32GB RAM at 1066MHz (I've deduced that processor is Nehalem Family) - 1 x 450 GB SSD - 3 x SATA Drives Although seems to run...

I am currently upgrading an early 2012 to 6 Core CPUs (washer stack method) and I have experienced some oddities: It does boot, but it shows a red diagnosis LED/ red lamp next to the front (when having the tray inserted) CPU. However, in system profiler it shows slots 1 and 2 as empty (which...