Wow. The price is quite good. Is there some website you bought this from? How many cores?
>>But a 24-core new workstation would be much more expensive
Tell me about it. I've been checking the prices of a dual 24 core workstation and it is around $7K.
http://www.ebay.com/itm/HP-Z800-Workstation-2x-Xeon-x5670-2-...
The one downside of this box is that the power supply is totally proprietary to HP. Well, the motherboard too. So if one of those craps out, you're done, unless you can locate a spare cheaply.
It's also reeeeaaally heavy and draws a lot of power.
What does Xeon have to do with training? You need a fast GPU (or apparently TPU). The CPU is relatively unimportant. Furthermore, you can roll your own algorithms (i.e. architecture) in TensorFlow. You don't have to use "theirs".
Now, you may think I'm crazy for designing something from scratch, I may be indeed, but how else can we discover/invent something totally new. I think I'm actually onto something given that the early results look quite promising.
I actually created a video demonstration of my AI Engine which you can find a link to it in my profile but I have done a crappy job of explaining the strengths of it [1]. Too much work, so little time.
Where I get stuck is figuring out new challenges to throw at the system. I find it funny that there is lots of discussion here about performance and tuning, and not so much about practice applications and valuable problems to solve.