To get 150Mbps you will also need a Wireles N adapter on your pc/laptop. Also you will need a strong signal. When running your test try downloading something that will download at 150Mbps at least. Also when doing the test try not to have other devices connected via Wifi (for the duration of your test).
Thanks a lot! y'a I've tried again, but still not catch that 150Mbps, but better than before, I just was wondering why they said transfer rate is 150Mbps and only 1/2 rate we got it actually! is it in theory?
The 150Mbps rate is the best it can do, so it will only transfer at 150 when under optimum conditions. Try copying something over the home network while nobody else is connected, you should get better speed then.
I have an N 300Mbps router myself. When connected with an N 300Mbps adapter, the best speed I have seen is 270Mbps.