Well, I've managed to solve my problem:
Get error: The semaphore timeout period has expired, resseting in 5 seconds.
Connection failed due to External host closed the connection"
by updating to 5.2.0
Did some tests, compared to DSTM.
Settings: 4x EVGA 1070Ti on 63%, core +200, mem +700
DSTM showed
2070 Sol/s. Average last 4h hashrate on Miningspeed
2060 Sol/sBminer 5.2.0,
2140 Sol/s. Average last 4h hashrate on Miningspeed
2130 Sol/s (0.2% rejected shares)
Looks very promising till now.
Thanks!