Yes, two PCs connected to 10G switch and still the same, the speed always less than 1.5Gbps.
Thank you for the clarification. What is the driver version used for both X520-DA1 and X520-LR1?
Please try installing the latest version in case you are not using the latest version.
Based on the test result. just to clarify whether the X520-DA1 or X520-LR1 connects with OR without using switch in between, the performance will always be slow in iperf ?
Please feel free to update me. Thank you.
I download drivers one week ago, but just in case, I download the hyperlink's driver and install again and reboot PCs, still the same?! no matter two PCs linked directly or a 10G switch between two PCs.
The speed always locate at about 1.35Mbps.
Please help by sharing your iperf testing paramters and the SSU logs.
You can download the Intel SSU at https://downloadcenter.intel.com/download/25293/Intel-System-Support-Utility, run the utitlity to generate the log then send to me.
I changed two PC's OS to Ubuntu Desktop 16.04 using default driver and get 10G link state(two PC connect directly), but the iperf speed still only 1.3Gbps?!
Good day. Please try the following:
1) Disable TCP offloading option in the advance property of the adapter
Go to device manager->Network adapter-> right click on the NIC->property->Advance->
Disable the TCP offload option
2) Check if there is "Above 4GB" option in the system BIOS, enable it if there is
3) Try on another PCI-e x8 slot within the same system
4) Check with Dell* support for similar issue or workaround , as we found your network adapter
bearing the partnumber of E66562-003 which is not an Intel retail part
5) You can also run the following iperf command
Host Tx> iperf –c xxx.xxx.xxx.xxx(ip of receiver) –i 5 –w 64K –l 64K –P 8 –t 20
Host Rx> iperf -s
–i 5 ; report display period in unit sec
–w 64K ; TCP window size at unit=kB, by default 8kB.
–l 64K ; traffic payload buffer at unit=kB.
–P 8 ; port# for payload transmitting and receiving.
–t 20 ; Testing duration y default 10 sec.
Hope the above information help.
Last few weeks we were busy in handling other problem, we will back to this case next week and reply soon, thank you!