Z840 can have secondary CPU.
(1) (1st CPU + 2 nd CPU) 2 x Intel® Xeon® E5-2637v4 3.5 2400 4C
(2) (only 1st CPU) Intel® Xeon® E5-2667v4 3.2 2400 8C 1st CPU
Option (1) is cheeper than option (2). What's the difference between (1) and (2)? Is it O.K. for me to buy option (1)? Is it kind of the advantage of using Z840?