What about something like this?

http://www.amazon.com/Intel-BC31S1P-Xeon-31S1P-Coprocessor/dp/B00OMCB4JI

$225 USD

The more expensive ones are not massively expensive. At 2g I could probably get one just with my tax return.

Or one might buy multiple Xeon-31S1P like we do now with GPUs.

You do need a motherboard that supports “Above 4G Decoding” and you turn it on in the BIOS.


https://www.pugetsystems.com/labs/articles/Xeon-Phi-31s1p-Cooling-and-Motherboards-614/

http://arrayfire.com/getting-started-with-the-intel-xeon-phi-on-ubuntu-14-04linux-kernel-3-13-0/

Cooling idea:

http://www.aquatuning.us/water-cooling/gpu-water-blocks/gpu-full-cover/19290/alphacool-nexxxos-gpx-intel-xeon-phi-31xx/51xx/71xx-serie-m01-incl.-backplate-black

or we could wait for Knights Landing:

http://www.zdnet.com/article/intels-next-big-thing-knights-landing/

Another coin that people have tried to use Xeon Phi to mine with is Primecoin.

Some kind of bare bones Xeon-31S1P rig may be more about getting the software right for future implementations than about delivering RoI.