Hi again guys, so finally I have my full speed ( nearly full almost ) on C5:
But was very strange, after spending a lot time doing some field tests, even with another brand new C5 at1 km. from A5c in clear LOS& similar high, a hill in front of AP, the results was very frustated:

Speedtest to 2 servers:

iPerf3 between 2 PCs:
1 km at 20 hz with MCS8 and 177/177 PHY Mbps. all ports 1 Gbps.

from the other side:

And the speed on that PC connected to the same switch Gigabyte like the A5c: ( same servers like before )


So, very frustated with the performance of that unit even at 1 km, in the night I was decided just to try a littlebit more and I change the C5s AGC from AUTO to manually ( was at 23 db setting up by remote A5c ) I let at 15 db and increase step by step up 20 db, after a few minutes to let algorithm to work well i feel that when I open new web sites was faster than before. So I tried another speedtest and here was:

With iPerf3, now at 3 km. is about 39-43 Mbps. maximum.
Today I repeat many speeds test with similar result, so that is great.
But, for resume Mimosa´s staff:
what kind of black magic is that ? 
Thanks.
P.D. Massimiliano, as I know the problem wasn´t my VDSL speed, router,etc. Anyway thank you so much to try to help me 