RT-N56U 5Ghz fades under load

[chaosmage]

Hello all,

Im using RT-N56 on the latest firmware 3.0.3.8-081, and have set up 5Ghz channel for gaming only.
When i stream my screen to my laptop, i have very high ping times (up to 60sec)

And the connection fails. I even can't connect to the router from my phone with 5Ghz.
Bandwidth is always around 2-3MB and seems to be not the issue.

When i download huge files, the latency grows but not that much:

There is no CPU bottleneck as Load Avg is 0.01 all the time.
Log does not show any errors.
2.4Ghz works fine at the same time.

Here are the settings:

Do you know if there is any chance to trace this behaviour?
Any ideas? I am completely stuck

Regards,
ChaosMage

 

[AdvHomeServer]

I'm also using Padavan's software, but with no problems. Check your wireless cfg for 5 GHz. Is it set for a/n, a only, or n only? Set it for n only and see if it improves.