Switched to 5 ghz with updated drivers (but no intel proset service etc) ...this is a pain it drops connection in few seconds after big transfer arrives. Also using second router from cisco connection is unstable signal is about 46db on first and 40 db on second router (basically 30 cm from laptop) both shows 144 mbit connection. Borrowed atheros works like charm.
Samsung support called to me Friday ... they want to check my laptop. Asked them about eventual cause of this issue and about resolution (waiting 2 weeks for drivers replacement in service is not my dream :-)) they said "Samsung engineer must to check your device ..."
I think I will try this way eventually in case drivers that will be relased at the end of q3 (that joe_intel said) fail.