Appendix B in the NSM Installer Guide has useful sizing requirements. Here is a snip-it that talks about logging on the Dev Server:
Device Server
A faster CPU supports higher sustained logging rates, improving scalability on the
Device Server. A modern Intel or AMD CPU (2.4GHz) or an UltraSparc III (1.2 GHz)
can handle sustained log rates of at least 20,000 logs per second.