Intel 10GbE Tuning under freebsd

[William Salt]

Hi All,
         I have just got a couple of 10GbE intel X520-DA2 cards to test. Im
running freebsd 8.1 on a super micro intel xeon server, and a hp core 2 duo
workstation, both machines have 4gb of ram.
Both are attached via sfp+ cables to a brocade turbo iron switch, which
simply has jumbo frames enabled.

Initial testing was pretty basic, i simply enabled jumbo frames, and
increased max send/recv buffer to 16MB, which should be more than enough.
I then ran iperf and managed to get approximately 5gbps, i was expecting
around 8.5gbps.
However, i realise that the ix driver probably needs to be tuned, as well as
the OS.

After a bit of googling, i cant find a tuning guide under freebsd for 10GbE,
or many recommendations, and wondered if anyone has already successfully
managed to tune freebsd with intel 10gbe nics, to gain a higher throughput?
If so, has anyone got any tips, or sample configs?

Thanks in advance
Will