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. :
PassMark Intel vs AMD CPU Benchmarks - High End
CPU Benchmarks - Choosing a Gaming CPU October 2013: i7-4960X, i5-4670K, Nehalem and Intel Update
CPU Benchmarks Hierarchy 2023: Processor Ranking Charts | Tom's Hardware
Intel Xeon E 2134 Sysbench CPU Multi Threaded Benchmark - ServeTheHome
CPU Performance: Synthetic Benchmarks - The Intel Haswell Refresh Review: Core i7-4790, i5-4690 and i3-4360 Tested