NFSv3, ZFS, 10GE performance

[Sven Brandenburg]

Hi,

I'm toying around with a potential ZFS based Fileserver and I'm curious 
as to what level of performance can be expected from FreeBSD 9 and ZFS 
exports via NFS(v3) over 10GE.
My current testing shows that while I can easily saturate the 10GE links 
with ttcp, I 'only' manage about 300MB/s through NFS. In my tests, the 
exported files should fit into L1ARC entirely (and can be copied to 
/dev/null on the local machine with several GB/s.. which seems about 
right reading from L1).
I would expect something in the region of ~900MB/s via NFS in my test case.

What can be expected for 10GE in terms of NFS throughput for a 9-STABLE 
client+server?
Are there sysctl's or similar knobs to fiddle with?

If helpful, I can provide more details.

Thanks :)
Sven