Intel Xeon E5-1660 vs 2650

Hi Y'all,

My question is vague, I know, but for someone like me looking to build a computer for work no play (CAD, 3D, Photoshop, etc...) I am currently debating between 2 CPUS:

Intel Xeon E5-2650 (8 cores)
Intel Xeon E5-1660 (6 cores)

With a very small difference in pricing, I am trying to know which trade off is better (the 2650 having more cores but lower GHZ speed or saving a few bucks and going with the 1660 with less cores but higher GHZ speed)? I need help and opinions. Thanks!