QUOTE(EON @ Jul 17 2017, 05:25 PM)
tried putting at the window got the same results

perhaps different part of the house? I found a funny situation when testing on my gf house last night.
All this while the best result yield was ~12mbps or so, there was once that I managed to get 20+mbps speed, and after that i never got that speed anymore and I ignored that. Odd enough, if i put it indoor at a lower position, but further from balcony glass door, the speed can go up to 16mbps. Last night i gave the modem another house tour, and just when I was about to give up, I just face the modem downwards facing the floor for the lulz, and surprisingly i got max speed of what my modem is capable of( well, somewhat ), at around 22mbps -25mbps
So moral of the story is that for high rise building, your management might have installed a few repeater, and i suspect mine is such case, and the repeated is located some floors below my gf's unit, and facing down surprisingly gives me ~20mbps most of the time, and 15mbps at peak hours.