Precision 5820 motherboard two chipsets

Chino alerted us of the nuances of this Dell pc model

Dell essentially made two distinct lines of pc

one called 5820 tower

the other called 5820 tower X-series

Both have LGA2066 socket 

one for Core X cpu (X299 chipset)

one for Xeon cpu (C422 chipset)

The X299 chipset mobo only supports Core X cpu

The C422 chipset mobo only supports Xeon cpu

I ran down a half deep rabbit hole

C422 chipset mobo

for Xeon cpu

X299 chipset mobo

for Core X cpu