Intel Xeon E3-1220 v3 vs Intel Xeon E5-2603 v4: What is the difference?
Intel Xeon E3-1220 V6 Linux Benchmarks and Review
Intel Xeon E3-1220v5@3Ghz/3.5Ghz(Turbo) 4C/4T @80 Watt | Precomp - Server Store
Intel Xeon E3-1220 v5 | Processor benchmarks | PC Builds
9-Way Intel Xeon E3 v5 Skylake Benchmarks On Ubuntu Linux Review - Phoronix
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 Xeon E3-1225 v5 review | 55 facts and highlights