My RouterBoard is RB433UAH , and RouterOS Version 6.1
the line speed 50M/20M
When I upgrade RouterOS from 5.2 tp 5.x the speed is normal
but when I upgrade to 6.0 or 6.1 now
if my Routeros is up time 7 or 14 day the line speed will down to 5M/1M
I must reboot machine will return normal
no queue rule enable
and RouterOS CPU usage is normal ,
sometimes CPU usage alway 100% , but line speed will not effect ,and need reboot cpu usage return normal