Faster with parallel command :

find /tmp/files -type f |parallel clamdscan --no-summary {}

Cannot confirm:

bench@sigil:/$ time find /usr/share/doc/texinfo -type f | parallel clamdscan --fdpass --no-summary {} | tail -n 2
/usr/share/doc/texinfo/AUTHORS: OK
/usr/share/doc/texinfo/NEWS.Debian.gz: OK

real    0m4,241s
user    0m3,101s
sys 0m3,324s
bench@sigil:/$ time find /usr/share/doc/texinfo -type f -exec clamdscan --fdpass --no-summary {} + | tail -n 2
/usr/share/doc/texinfo/AUTHORS: OK
/usr/share/doc/texinfo/NEWS.Debian.gz: OK

real    0m0,299s
user    0m0,015s
sys 0m0,033s
bench@sigil:/$ time find /usr/share/doc/texinfo -type f | parallel clamdscan --fdpass --no-summary {} | tail -n 2
/usr/share/doc/texinfo/AUTHORS: OK
/usr/share/doc/texinfo/NEWS.Debian.gz: OK

real    0m4,273s
user    0m3,222s
sys 0m3,513s
bench@sigil:/$ time find /usr/share/doc/texinfo -type f -exec clamdscan --fdpass --no-summary {} + | tail -n 2
/usr/share/doc/texinfo/AUTHORS: OK
/usr/share/doc/texinfo/NEWS.Debian.gz: OK

real    0m0,343s
user    0m0,004s
sys 0m0,047s