I tried, and with a 2,7 GB file it take 40 seconds, so 553 Mbps. Now it's better ! Thank you ! :)
It was already set to 40 MHz. I switch it to 80 MHz, and it's better. 553 Mbps with a large file (2,7 GB).
I don't want the N wifi, only the AC wifi.
Yes, I already use Wifi analyzer. ;)...