I have posted months back about the 100% cpu issue in mikrotik routerboards with RoS v4.
Other users also posted about crashes of the routing service.

After upgrading RB433AH from 4.13 to 4.16 I haven't had any issues WITH 100% cpu for two weeks or so. After that nothing changed in configuration of the routers but same problem here until now.
The bug (I say it's a bug because it didn't have to do anything with performance-It was just a display 100% issue for us) happened strangely every week on the exact day of the week.
At first we thought it was an attack.Checked firewall rules - Nothing there.Tried to reset counters the day before and the problem stayed. We came by with a workaround which was to reset every week at the exact day.
We have a bridged network of 433AH's with v4.16 and what we where doing was scripting them to reboot every week.
That thing sucked...

After 3 months of monitoring 2 RB433AH we've disabled all the ports that are not used or even those who had no traffic (like some ether ports) and the problem for us is pretty much solved. The only thing that changed was disabling those ports.

I will although post about the uptime that we can achive with this config.

PS:I know it's a v4.17 out there but there isn't much different as I can see in the changelog about this thing.

If problem was solved just by disabling bridged ports then I would suggest to check whether there was a L2 loop.

Will check and post back.Thanx for the responce

If problem was solved just by disabling bridged ports then I would suggest to check whether there was a L2 loop.

mrz there isn't any l2 loop. Could check because it's a small network of 3-4 routers.
The ports we disabled are ether2 and ether3. They were not bridged. They were not in use and had no traffic.

An l2 loop would most propably cause a real 100% cpu. I am calling it a bug because it is not affecting performance,winbox,commands or anything like that.Only the value of the cpu at 100%.