Clamav load

[emm1]

Hello, Im running the newest MailScanner from FreeBSD 6.2 ports,
4.60.8 and clamav 0.90.3 and I am experiencing very slow scan times
and high loads.

 2240 root        1 107    0 39056K 36684K RUN      0:18 44.21% clamscan
 2248 root        1 108    0 38272K 35900K RUN      0:07 31.08% clamscan
 2256 root        1 108    0 11852K  9452K RUN      0:03 23.99% clamscan
 2262 root        1 108    0 11752K  9352K RUN      0:03 20.87% clamscan
  656 clamav      1   4    0 39480K 36996K accept   0:27  0.00% clamd


As soon as I turn the virusscan off in MailScanner.conf everything is fine.

Any suggestions?

Thanks!