> PtP-Link: Distance is 8 km both 2.8.16 2,4 Ghz Celeron and 1 Ghz Celeron
> Signal TX and RX about 68-70
ok, let's go : I consider -70dB signal on 8km link to be kinda weak, it could be stronger. As you probably know, there are three things that count with OFDM modulation:
a) signal strength, every decibel counts (!!)
b) interference on given frequencies - definitely this is MAJOR factor of performance
c) directionality of signal - OFDM does not like sector / panel antennas, PtP links are ideal
Next thing: try locking your nstreme settings for 36Mbit speed:
set name-of-interface supported-rates-a/g=6,9,12,18,24,36Mbps
set rate-set=configured (!!!!!!) - this will LOCK your setting to 36Mbit max.
If you want to lock your card to 24Mbit and 36Mbit datarate only, delete 6,9,12,18Mbps figures from supported-rates-a/g setting - but beware that if you don't have enough signal to hold 24Mbit connection, the link will drop and won't transmit traffic AT ALL. Don't forget to change your basic-rates-a/g to 24Mbit/s also.
Yes, could be there is different behaviour between legacy and nstreme drivers - legacy holds your 36Mbit settings whereas nstreme could be 'speculating' or 'behaving' little bit differently. Lock it with above settings and there you go.
Also, I feel that your performance could be little bit higher for the signal strength you have. Are you sure there are no 'cleaner' frequencies in your band ? Did you try another freq ?
Let me know if my setting did help you to lock cards to 36Mbit.