Asus rt ac56u 2.4ghz slow

I just bough this router yesterday and i have major issues with the 2.4ghz wireless 11n mode.

First of all ping is fluctuation up and down, and not responding:
https://www.dropbox.com/s/dtwtjq54fz...827_091643.png

Any online gaming is impossible... Running just 2 torrents makes is also impossible.

Second windows says connection speed is over 100mbs https://www.dropbox.com/s/77jjmmbc2i...827_091746.png

But i can only get 1MB/s locally and outbound. Not even 12mbits which is the speed from my internet provider.

What I tried.
1) Reset router. No help. Ping might be a bit more stable. But speedwise no help.
2) Installed merlins firmware. Same result as 1.
3) Tried locking channel bandwith to either 20ghz or 40ghz. 40ghz a bit more stable.
4) Running at channels 1, 7, 11. Same result. Theres many wireless in my area! http://db.tt/PmdLX8aO
5) Tried without encryption. Same as 1
6) Other computers. tried 11a in 2.4ghz and 5ghz speeds between 16-28MB/s.

Settings:
http://db.tt/vFqEA7E9
http://db.tt/4ZyGsjJu

System info:
http://db.tt/vpHaOsF6


Currently I think replacement is my only option? Any suggestion?