Have you tried other wireless infrastructures to connect to? Also what type of bandwidth it being offered on the current wireless AP. Does your radio card have to deal with a lot of other wireless users around you.
There are a few options that we can exercise to improve your performance, you can switch the 6205 to connect exclusively on the 5ghz band free from 2.4ghz saturation. Lets get those details hammered to see what else can be done.
thanks a lot for your answer. If i connect to other Wifis its the same problem. The Wifi is used by maximal two other users. Where can i check wich type of bandwith is offered and where can i change the settings?
You may check the settings for the Intel® wireless adapter as indicated in the first article below. You may also need to review some settings from the router itself. The CMD command netsh wlan show interfaces can give you further information about your connection.
There is also the possibility this issue is related to software or operating system corruption.