Slow SSH on RPi 3 in local network (5 GHz Wifi for RPi3)

[Pcornat]

Greetings,

My problem is the following : I was using Raspbian and then I decided to use ALarm just like on my laptop (Arch x86_64).

On Raspbian, the network was great, no problem on SSH and all. But now, it is really too slow, like I type in my terminal and 2 seconds later the letters appear…

I googled and found nothing in the same situation nor the same configuration like mine.

Thank you in advance.

PS : English is not my native language, sorry for the mistakes.