The dual ethernet in the current Mac Pro are only 1 GigE and gets around 100MB/s (real world)[0]. I aggregate the two cards to get better speed. Even a 10 GigE couldn't max out the SSDs in these machines which are 2GB+/s r/w.
[0] by real world I mean on a properly configured network. Many companies don't have that though so you often see "gigabit" speeds in the 30-50MB/s range.
[0] by real world I mean on a properly configured network. Many companies don't have that though so you often see "gigabit" speeds in the 30-50MB/s range.