Waaronb is correct that any of the Processor options (for your DL160G8) can bee installed into your system.
In your case of wanting to use an Intel Xeon E2650 processor, please use the HP sales P/N of 662931-L21. I would also order a replacement heat sink as well. This will have a new Thermal pad for use on the new Processor. This can be skipped if you have access to a better quality of Thermal compound (paste). Artic Silver is what I would use if I were doing the upgrade.
By sure to update Bios to the latest one for your server, use good static dissipation guidelines while replacing the Processor chip. Consult the users/service guide for procedures, step by step.
Regards,
Louis