Perfomance problems on 10Gbit NICs

[lohmag]

I'm testing speed with iperf on two Intel x550 T1 NICs Windows - FreeNas. When iperf server running on Windows and data sending from Freenas - speed goes up to 10Gbit, but when server runs on Freenas and it receiving data from it - max speed is 2Gbit.
Copying files show the same result - read from Freenas 700MB/s, writing only 165MB/s
What is the problem guys?

 

[joeschmuck]

What is the problem guys?

The problem is those damn forum rules. Please post your system specs per the forum rules. There are several hardware items which could factor into your issue and without knowing that data then we are just taking complete wild guesses which is not very scientific. Also are the NICs connected directly to each other (no switch)? Lastly, typically (not always) we find out that the issue is on the Windoze machine. I'm not saying that is the issue here but it is the typical end result.