I do a bandwith test with Iperf on the i.MX6, the phy is AR8035 connected with a RGMII Interface. I have done an eyediagram and this looks very good also when I heat up the board. But When I do the Iperf and heat up the board the Ethernet bandwith goes down to 0 Mbit/sec. I think it is the RGMII Interface. Did someone have an idea?