I was given this HP Proliant DL180 G6 (Xeon E5506, 4GB RAM) without power supply. As a newbie in that domain, I was shocked by the size and weight of that thing!
List of Intel Xeon processors - Wikipedia
HP Z800 Intel Xeon QC E5506 2.13 GHz 8GB 250GB NVS 290 Win10 [Z800-4] - $950.00 : Professional Multi Monitor Workstations, Graphics Card Experts
SLBF8 (Intel Xeon E5506)
Intel Xeon E5506 - AT80602000798AA / BX80602E5506
Intel Xeon E5506 Quad Core Processor - ServerCart
Intel Xeon E5506 2.13GHz 4MB 4.8GT Quad-Core CPU Processor SLBF8
Intel Xeon E5506 2.13GHz 4MB 4.8GT Quad-Core CPU Processor SLBF8
Intel Xeon E5506 - AT80602000798AA / BX80602E5506
Server HP Proliant ML350 G6 2 X Xeon E5506 16GB RAM + 4 X 1TB Raid 1+0 RS232 | eBay