connectx-5 max speed 68Gb?


I’m just starting to use the connectx-5 with iperf3 to replicate one lab that i created with the connectx-4 but no luck at the moment.

I used the same 2 x server hardware (Supermicro X9DRi-LN4F+ - E5-2600 2U with 2 x 2.60 GHz Eight (octa) Core Xeon E5-2650 V2 and 48Gb of RAM)

and while with connectx-4 i can reach 98Gbps (RX and TX) with connectx-5 i can reach only around 68Gbps.

If i connect one of the servers with connectx-5 with one of the connectx-4 server and do traffic connectx-5 ===> connectx-4 TX is 98Gbps but when i do it

in reverse connectx-4 ===> connectx-5, RX of the connectx-5 is 68Gbps.

I have exactly the same Os (centos 7.4) with the same config (i even try to update the OFED drivers to the latest).

Do anyone experienced the same?



We don’t expect this behavior.

Please look for errors in ethtool statistics.

CRC or PCI errors

All phy counters

Out of buffer counters



Hi Amir,

Thanks for your tips, i will check it (and post here is i don’t see anything wrong) when i’m back from holidays.