I am hoping this Monero fork to RandomX will make my decision to own around 100 pcs Xeon X5660 worthwhile, haha!
I am getting close to 1500 H/S each on them... I forgot my power data (need to re-measure) but that is *under* the 90 watts max of the CPU... so 16 H/S per watt is the minimum.
Thermal Design Power for the Xeon X5660 is 95 watts. The actual power used can be upwards of 50% above this value just for the processor alone.
http://www.cpu-world.com/CPUs/Xeon/Intel-Xeon%20X5660%20-%20AT80614005127AA%20(BX80614X5660).htmlAlso you will need to consider the power used by the memory, motherboard, GPU and the efficiency of the power supply.
I have tested Dell T5600 workstations with dual Sandy Bridge E5-2640 and dual E5-2670 Xeon's. These are the results:
Dual E5-2640, 12 threads, 4554 H/s, 310 watts: 14.7 H/s/W
Dual E5-2670, 16 threads, 6406 H/s, 357 watts: 17.9 H/s/W
The E5-2640 also has a Thermal Design Power of 95 watts
http://www.cpu-world.com/CPUs/Xeon/Intel-Xeon%20E5-2640.htmlAssuming that the two of then used 190 watts that still leaves 120 watts used for the memory, motherboard, Quadro 600 GPU and the 80% efficiency of the power supply.
Sandy Bridge processors are more efficient vs the Westmere processors which the X5660 is.
For actual power used you really need to measure at the wall.
Your guess of "16 H/S per watt" is not realistic.
THANKS for the information. How much memory did you have installed for those E5-2640 and E5-2670 tests and how fast is the memory? Also which OS did you use?