Got the fourth rack 100% done:

$125 ?! I can't find them for any cheaper than 275+ EUR so that's a steal! Especially considering this ...

Dell T5500 is the equivalent of a HP Z400-series
Dell T3500 is the equivalent of a HP Z600-series
Dell T7500 is the equivalent of a HP Z800-series

... and T7500 seems to come with 1100W PSU by default. And with two PCie 16 slots with upto 225W (instead of 150W of HP Z400) out of a total of the similar 4x PCie according to http://www.dell.com/content/products/productdetails.aspx/workstation-precision-t7500 . It sure has great perspective.

Hello all,

Stoked to see that I can actually do something with an old T5500 that was about to be tossed into the dumpster at work...  It came with a 1GB Nvidia Quadro 600 card and 12 Gb Hynix Ram.
A quick search brought me here and since I had been planning to build a miner I struck gold it seems...

First problem is that the system won't boot up.  I got a blank HD in it, but I have the dreaded "2-3-4 blink with solid amber power light Pb7" code. Tried the usual and I am now looking at replacing the X5650 CPU.  If that works I am planning to add a few 580's and fire it up.

Love to hear if someone else has had to work through this particular issue before and has insights.  I'll post my build notes along the way...