CPU-Z Benchmarks on various Synology models - Hope this helps give a rough idea of the CPU power difference between models. Also included 2 other VMs running on Windows Hyper-V Server. :
Intel 14nm Broadwell-EP Family Launched - Xeon E5-2600 V4 For Next-Gen Workstation Platforms With 7.2 Billion Transistors
Intel Xeon E5-2699 V4 benchmarking the top end E5 V4 CPU
Rendering Performance - Intel's Xeon E5-2600 V2: 12-core Ivy Bridge EP for Servers
Intel Xeon E5-2643 v4 vs Intel Xeon E5-2690 v4: What is the difference?
Linux Performance - Intel Haswell-EP Xeon 12 Core Review: E5-2650L V3 and E5 -2690 V3
Dual Intel Xeon E5-2697 V4 Benchmarks - #3 in the lineup