FreeBSD as a gaming server platform

[Matt]

Are there any kernel tunables that you would recommend setting to
increase performance on FreeBSD 6.x for running gaming servers (e.g.
Quake 4, CS:S, etc)?  It appears that the default settings are not
performing nearly as well on FreeBSD as they are on Linux on similar
hardware, and it seems to be something network related.  I did some
searching for settings that could increase max packet rates and such,
but to no avail.

Thank you,
Matt