I have been having this issue for some time, but am finally getting round to post it.
It seems after some days (not sure how many), something happens with clamd and it stays at 40% cpu utilization.
It does not do this when initially started, so i guess it is after running from some scheduled times.
shows as user root, /usr/sbin/clamd -c /etc/clamav/clamd.conf -pid=/var/run/clamav/clamd.pid 41% CPU 10% MEM
as i say, when initially started, everything is normal. i tried changing the user to clamav in the config and some other parameters, but it seems to get reset to defaults each time.