udp performance 10gbe intel x520

good morning,

i've the following issue:

i've a  FPGA able to send up to 9 Gb/s. it has been tested on in loopback mode since the board has up to four 4 sfp+

i've a server supermicro with intel x520 board with windows server 2014 .

i'm sending UDP jumbo packet  on one port (65504 byte per datagram)

the application is written in cpp and the thread loop code is well designed.

i'm notice that also at low speed packet are lost.

seems buffer overwritten of datas incoming.

thanks a lot in advance

LM