Since 6.x OS version we have strange problem with OTik U-5HnD I wrote about this long time ago but its not fixed yet, ones a week or on every 2-4 days CPU some how for some reason goes over 50% in tools profile I see wireless is above 40-45%, clients throughput is very slow, or in some cases clients disconnect/reconnect, only solution is reboot and OmniTik start to operate normal. This problem is only on OTik U-5HnD never happen to UPA-5HnD.

Tried wireless-fp and wireless-cm2
My config is simple all interfaces are in Bridge I m not using security, not using firewall, all clients are SXT wireless protocol is set to nv2.

What RouterOS and firmware version? I recall similar issue with 6.1x

When you notice high load, open Tool > Profile to see what's loading the CPU...

I'd upgrade to 6.32.3, making sure firmware (System > Routerboard) is up to date also.

Are you graphing on the device itself?

The problem is mostly due to lack of memory. 32mb version works much worse than 64mb version with ros 6. Just my observation discussed on this forum long time ago.

pukkita : "in tools profile I see wireless is above 40-45%"
Ive had used almost all 6.x OS ver. problem persist,
we have almost 50 OmnTiks in our network 50% Are UPA OmniTIk witch dont have this problem , all up to date firmware and OS

jadra yes maybe this problem is related to lack of memory, still there is no official answer from Mikrotik support
Last time I've installed OS main package also I disable some of unneeded packages (dhcp,hotspot,ppp,routing,security)
system resource> print
free-memory: 7.2MiB
total-memory: 32.0MiB

On some OmniTiks I get up to 10-11MiB free memory but that is
What can I do.

jadra what about interfaces queue types now wlan (by default) is set to wireless-default as I remember there were some changes in 6.x queue types + it was added only-hardware-queue
what if I change wlan queue type to only-hardware-queue is it possible to help because wireless is triggering high cpu

If you install selected packages individually then you wouldn't need to disable the unwanted ones. Official answer is that 32mb is enough and when there is 1-2 mb of free ram the router can perform well. My observation says that if free ram goes under 5mb the router is hanging, lagging, running cpu at 100%, forgetting to answer on snmp requests, logging codes of blacklisted programs and finally it reboots itself. Then it works good until the free memory goes under 5mb again. Simply 32mb of ram is not enough obviously for omnitik even rb750 or rb751 that are the same work nicely. Hard to say if queue type change for interfaces can help, sometimes ethernet default is better than only hardware queues on ethernets but you have to try on your own.

So only solution is to replace these OmniTiks with OT UP ?!? I had no replay from support.

To buy an omnitik is kind of roulette. Sometimes you can win 64mb version even you weren't buying the -A version.