The most dramatic is the setting of the roaming frequency (signal level threshold). It is even possible to stop it completely. If you're like me, with no mobile connection and a very weak signal, this option is perfect: it avoids the constant renegotiation ra which totally destroys bandwidth already parsimonious. The download is not interrupted constantly with a sinuous curve: the curve is still small but flat. Invaluable improvement over my previous card that also offered a similar signal quality with a single antenna.
The second option seemed useful ui is the mode "gaming / multimedia". I have not found a precise description of its effects on the management of packets but apparently dropped packets are better managed, which seems optimal "live" connections such as voice or video communications, streaming and gaming Online.
I take off a star for a pitiful support. Who still has an optical drive for pilots supplied on a mini CD that besides all the players will not play ... CSL is not only hyper generic brand but also totally absent from the non-German web. A fairly good documentation is available however on the chipset used a Ralink T5572.
if you do not need the "ac", the chipset offers the best of "n". Price is finally justified. View may be elsewhere than at CSL.