since first tuning of FreeBSD TCP/IP stack somewhere in 4.x, I’m typically fiddling with the /etc/sysctl.conf contents from time to time. you know, just to tune stuff. in the meantime, a lot of things has changed in FreeBSD TCP/IP stack, including introduction of modularity. however, MacOS X that is based on FreeBSD is much more conservative and some options are not available. therefore, on my MacOS systems I use following /etc/sysctl....
if you have to pack a lot of things, using sheer power of modern multi-core/multi-threaded CPUs may come handy. unless… the tools you’re using are not enabling that by default, and you suffer running everything on one core/thread. as I spend most of my time recently with FreeBSD and MacOS the tools I typically use are command line. therefore, for every gzip - consider using pigz. and for bzip2 - consider using pbzip2....
FreeNAS is special edition of tuned-up FreeBSD, with GUI available over WWW to enable easy setup and maintenance. i had to migrate recently my old Synology 1815+ thanks to well known Intel SNAFU with Atom CPUs. interestingly enough, even Synology own service department declined to RMA the NAS, without even discussing the situation. so i managed to setup quickly 12x 3.5" bay server. i had five 3.5" 8TB HDDs from Synology that i wanted to rescue data from....