AC66U slow wireless speed

Hello,

I have an Asus RT-AC66U router with Merlin Fork 380.57_0 firmware. I use a Macbook pro retina late 2013 and have a 1000 Mbps upload and 200 Mbps download Internet connection.

The problem is my wireless/internet speed is slower than it should be.

Here the results from speedtest.net:


I am connected to ASUS_5G.

5GHZ settings are:

Hide SSID: No
Wireless Mode: Auto...

AC66U slow wireless speed