Question: When using tools such as Iperf to test the 10-gigabit network card, it can't reach 10-gigabit, maybe only about 5G. What's the matter?
A: The network test tool is to test the end-to-end link speed. The 10-gigabit network card can meet the bandwidth requirements by using the gold finger link. For example, PCIe Gen2 will use the x8 interface, PCIe Gen3 will use the x4, x8 interface, PCIe Gen4 will use the x4, x8 interface, etc. to meet the single-port, dual-port, multi-port 10-gigabit requirements.
When the test speed cannot be reached, in addition to checking the normal link connection, it is also necessary to pay attention to checking the contact between the network card on the machine and the PCIe slot on the motherboard. In rare cases, the system identification is incorrect due to the contact between the gold finger and the PCIe slot. For example, the contact of x4 and x8 only recognizes the width of x1, and then the tested speed cannot be reached at this time.
Under Linux system, you can view the information recognized by the system through lspci - vvv - s
. Under Windows system, you can view it under the network card attribute.