Hi all, We found that Intel 9000 series wifi cards have tx performance issue on 5G network. Here are the test result. Client(10.101.46.25) is the platform with 9260 wifi card on 5G network, and server(10.101.46.219) is another machine with ethernet network. kernel v4.15-rc5 with firmware API 33 acelan@u-Kabylake-Client-platform ~ % iperf -c 10.101.46.219 -er ------------------------------------------------------------ Server listening on TCP port 5001 with pid 2248 Read buffer size: 1.44 KByte TCP window size: 85.3 KByte (default) ------------------------------------------------------------ ------------------------------------------------------------ Client connecting to 10.101.46.219, TCP port 5001 with pid 2248 Write buffer size: 128 KByte TCP window size: 85.0 KByte (default) ------------------------------------------------------------ [ 5] local 10.101.46.25 port 54308 connected with 10.101.46.219 port 5001 [ ID] Interval Transfer Bandwidth Write/Err Rtry Cwnd/RTT [ 5] 0.00-11.06 sec 7.75 MBytes 5.88 Mbits/sec 1/0 77 7K/165143 us [ 4] local 10.101.46.25 port 5001 connected with 10.101.46.219 port 38816 [ ID] Interval Transfer Bandwidth Reads Dist(bin=0.2K) [ 4] 0.00-10.31 sec 77.0 MBytes 62.7 Mbits/sec 55729 49:23:176:59:1140:294:168:53820 ------------------------------------------------------------ With firmware API 34, no luck acelan@u-Kabylake-Client-platform ~ % iperf -c 10.101.46.219 -er ------------------------------------------------------------ Server listening on TCP port 5001 with pid 2138 Read buffer size: 1.44 KByte TCP window size: 85.3 KByte (default) ------------------------------------------------------------ ------------------------------------------------------------ Client connecting to 10.101.46.219, TCP port 5001 with pid 2138 Write buffer size: 128 KByte TCP window size: 187 KByte (default) ------------------------------------------------------------ [ 5] local 10.101.46.25 port 43560 connected with 10.101.46.219 port 5001 [ ID] Interval Transfer Bandwidth Write/Err Rtry Cwnd/RTT [ 5] 0.00-10.01 sec 896 KBytes 733 Kbits/sec 1/0 58 7K/140474 us [ 4] local 10.101.46.25 port 5001 connected with 10.101.46.219 port 38844 [ ID] Interval Transfer Bandwidth Reads Dist(bin=0.2K) [ 4] 0.00-10.11 sec 79.8 MBytes 66.2 Mbits/sec 57744 37:6:191:52:1236:413:143:55666 Any ideas? Best regards, AceLan Kao.