Very good dual WLAN USB stick, driver update for 5GHz necessary

I bought the USB stick for my netbook, because the internal wireless card works only in the 2.4GHz band, but the 2.4GHz band is overcrowded hopelessly through the neighborhood and the transmission reaches correspondingly poor values.
In the 5 GHz band, I am currently the only user, so the best conditions. The reception with the stick is very good and in the 2.4GHz band in both bands much better than with the internal card.
With a Fritz box 3390 I can do in the 5 GHz band in the next room (through two walls) over 100Mbit / s, the 2.4GHz band is only about 25Mbit / s by the multiple use of channels.

Under Windows 7 works with the driver on the CD once all the best.
Under Windows 8.1, the internal driver is used. This works but not the 5GHz band. On the homepage of the chip manufacturer (Mediatek.com) there is the current version 5.1.7.0 with the well under Windows 8 everything is working fine.
But an update of the driver is also recommended among other versions of Windows (XP, Vista, 7)

The reference to this driver I have received from the support of the manufacturer CSL computer within an hour of sending my request. But kudos and thanks to the support!