"Intel Dual Band Wireless-AC 7260" does not work with AC

Hi there.

I have the "ASUS RT-AC66U" router.

Now i bought the "Intel Dual Band Wireless-AC 7260" for my MSi GE60 notebook with Win7x64 home premium. The old WiFi card was "AzureWave AW-NB114/H"

I replaced the old WiFi card with the new and installed the latest driver(16.10.0.5), downloaded form the Intel website.

In the control center of Windows i can't choose the AC networktype. Only b/g/n. (see attached screenshots)

When i connect to the 5GHz network it works only with the "a" type. 5Mbit/sec. (see screenshot)

(sorry, the pictures are in german, but i think you will see my problem)

Do i have to activate/change somethink?

Thank you.