LOT OF 2 Intel Xeon X5670 2.93GHz 12MB LGA1366 6-Core CPU Processor SLBV7 | eBay
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 X5670 Dual 6 Core Processor Benchmarks and Review