PMP450 AP and SM test speed utils iperf P=1 speed only 10Mbit

Test speed used iperf or other utils with using one thread  gives the rate of not more than 10Mbit / c

On Etnernet one thread gived 90 Mbit/c 

Why PMP450 one thread gived download or upload only no more 10Mbit/c

Several factors can cause this. Remember also, that this is a wireless link with its latency!