NIC transferring twice its max rate

[Rob Owens <rowens@ptd.net>]

I've got an onboard NIC, supposedly 100Mb.  I've been doing a dd over
ssh for the last hour, and iftop tells me that I'm transmitting at a
steady 186Mb, while receiving about 1.2Mb.

I read up a bit on full duplex, and as I understand it full duplex means
the NIC would be capable of transmitting a theoretical max of 100Mb
while simultaneously receiving 100Mb.  My card seems to be transmitting
at nearly double its theoretical max.

Is this possible, or is iftop lying to me?

I've got gigabit networking between the two computers, and the second
computer has gigabit ethernet.

-Rob