Criteria for Hardware [on hold]

I have an upcoming test where a question might be:

We need to buy 300 new PC's, the criteria for CPU-power, interfaces, 
RAM, and graphics are already set. Besides these which hardware criteria we have 
to consider.

Other criteria I could think of are: The casing, how to handle heat, power supply and consumption, hardware security, mass storage options.

Would be the number of CPU-cores a valid answer or is it included in CPU-power?

I'm unsure if the main-board gets fully specified by the interfaces, are there other criteria for it?

If i messed a few it would be awesome if you could name them.