Hi luis664, if you have such low signal strength, even when you are close to the router, the problem may be related to the antennas.
I have an old 802.11g router very close (less than a meter) to the system with AC7260 and I am getting five bars (-34dBm), or 99% signal strength after typing “netsh wlan show interfaces” at the command prompt.
The other router I am currently connected to is 802.11n and it is, at least, thirty meters away from the same Ultrabook*. While I am connected at 5 GHz I am getting four bars (-60/-70dBm), or 80% signal strength. Another system with a different adapter gives me three bars or 60% from the same router, band, and location. No problems whatsoever.
I believe you should be getting similar results depending on the distance; otherwise, you may need to contact the system manufacturer.