Depends. I'll assume you are using CIFS.
If you are running a RAIDZ1 or RAIDZ2 you need MUCH more RAM. The manual basically says you should have 6GB minimum if you plan to use ZFS and want reliability as well as performance. Your CPU is a little low on the frequency side for CIFS. CIFS is single threaded, so Ghz is really what matters, not the number of cores.
I will tell you that having intel NICs on the server as well as the desktop/workstation really mattered for me. For me it was an instant increase in performance of about 20%.