Transfer speed on N5K

[fsck]

You can always up that windows sizing.  128kb is a good place to start and keep going up.

Judging by your last transfer in the 250mb this one looks like its close to doubled in the 450mb range?  Is that correct?

What servers and NIC's are you using?  Are you going to be happy once you eventually see 800ish?

I changed it even higher and noticed that past 512kb it showed the same results of 525Mbits/sec. 

We are using Intel Ethernet Converged Network Adaptors X520-DA2 with Twinax cabling.

Yes, I would be very happy with 800ish as that would be the max, give or take correct?  Since it's theoretically 1,250 but of course we have to factor in TCP overhead.