ixgb TSO performance degrades by ~30% between 7.4 and 8.2/9.0/9.1

[JMP]

Hi,
I saw a post at 
http://lists.freebsd.org/pipermail/freebsd-net/2012-October/033660.html
discussing performance degrade on ixgbe when enable TSO.

We are experiencing the same issue on FreeBSD 8.2 with the latest ixgbe 
driver (version 2.5.8) from Intel.
I am not sure if this is a driver issue or a system issue and if there 
is a fix for this issue?
If yes could you please let us know where we can find the patch?

Many thanks in advance!

James Pan