I make this topic in order to help all those people that have the same problem as i did to fix once and for all, their problems with drop outs . The solution is simple and easy and you don't need to buy a new card.
The driver version and date should be as above. It works perfectly for three weeks now under windows 8.1 without a single drop out.
So all you have to do is to find and install driver version 15.0.0.75. For me it was on lenovo's site under windows 7 wifi drivers which where old and not updated by lenovo.
But let me clarify one thing. I read alot of "simple that make things better" solutions like changing roaming aggressiveness and some other properties or installing newer drivers or roll back the drivers (which didn't work under windows 8.1 as they dont have old drivers), or even to reverse(omg) the two cables of wifi card. Nothing of these will work out trust me. All i had was the feeling that it was better than before and then, drop out.....
Anyway i hope i helped some of you find some peace
