now considering that it is a workstation, and that 12cad.com recommends for a
workstation;
Intel Xeon E3-1220V3 Haswell
8GB of RAM, Nvidia Quadro K620 2GB
1TB 7200 RPM HDD, Windows 8.1 Pro
And comparing the
E-2650 versus the E-1220 (could not find a comparison with E-2660) as the E-2660 will beat the scores of the E-2650 presumably.
I would say your HP z420 should be.