Not necessarily. With GSO, you can send near 64K datagrams, which will then get split into MTU sized datagrams in the driver or on the card. But if you're sending a 1G file, that's a lot of 64K writes.

And then you have to consider what is seen on the other end. Is GRO configured on all the endpoints these datagrams are going to? They won't necessarily see those near 64K datagrams, but lots of smaller ones.