I have upgraded three of my boards to rc14.

In one of these boards the CPU usage is always more than 60%, without traffic. It's very strange.

Can someone give me a help?

are you sure no traffic? unplug cables.

also try to disable packages one by one, and see if one makes a difference.

From which version you upgraded?
Are you using Nstreme?
Do you see any performance degredation on your router?

I also see on my routers with nstream-dual high cpu usage , from 30% it rase to 60%

also performanse on nsteam-dual is worse than ever.
i upgraded from rc12 to rc14 and
with rc12
RX/TX 25Mbps / 33Mbps
with rc14
RX/TX 11Mbps / 30Mbps
test was before upgrade and right after upgrade.

using P4 dual-core , 1Gb ram , 512 Flash disc , asus board
Atheros XR5 ,actually i think signal better with rc14 for some 3db

I also see on my routers with nstream-dual high cpu usage , from 30% it rase to 60%

also performanse on nsteam-dual is worse than ever.
i upgraded from rc12 to rc14 and
with rc12
RX/TX 25Mbps / 33Mbps
with rc14
RX/TX 11Mbps / 30Mbps
test was before upgrade and right after upgrade.

using P4 dual-core , 1Gb ram , 512 Flash disc , asus board
Atheros XR5 ,actually i think signal better with rc14 for some 3db

please provide us with the support output file from your router where you have slow perfomance. Send that file to support@mikrotik.com

From which version you upgraded?
Are you using Nstreme?
Do you see any performance degredation on your router?

I have upgraded from 2.9.50 and I'm not using NStreme.

One WDS station interface and other AP Bridge. No traffic and 50% and higher usage.

Ok
my rx / tx was on 5700 / 5580

when i set rx on lower freq it works ok ,
but question is , why on rc12 works ok on this freq. and on rc14 not
to make sure , i tested on other dual link with rc14 , and same situaton.

Ok
my rx / tx was on 5700 / 5580

when i set rx on lower freq it works ok ,
but question is , why on rc12 works ok on this freq. and on rc14 not
to make sure , i tested on other dual link with rc14 , and same situaton.

there is no change for Nstreme2 only using framer-policy=exact-size could crash with kernel panic.
Make the support output file from both versions using the same freqeuncy and when you are sending the traffic.