Why does an HP Z620 workstation include a larger 800-Watt 90% efficient power supply?

A.
To support enhanced cooling features that reduce operation noise

B.
To support amazing expandability in storage and processing power

C.
To support multiple USB charging ports for faster results

D.
To support dual processors and high-end graphics

Explanation:
http://www8.hp.com/us/en/campaigns/workstations/z620.html (brings your ideas to life
faster)