As some folk have commented on its speed i thought i'd see if there was any difference between HDD/USB... obviously nothing better to do some would say - but no-one else has attempted these frontier's of research! Downloaded today's current version - put a copy on HDD and a copy on portableapps USB. USB is U1 and type 2.0 cable.
Test! was on another USB drive used for data storage not portable apps.
With avast still running (not such a good idea but i forgot to turn it off)
HDD - 1m 37s
USB - 1m 37s
With Avast turned off
HDD - 1m 10s
USB - 1m 10s
Simple conclusion no difference of speed between HDD/USB - turn off resident shield whilst using Clamwin.
As i see it Clamwin is fine for what it's designed for checking floppy and small USBs. I wondered if it could be used on the HDD instead of Avast/AVG as i once had an update which somehow knackered the registry settings and i had to format the whole drive. To me a the great advantage of portableapps is not writing to the registry so one can just delete and install - confident that one doesn't upset anything. Portability for me is just a benefit for occasional use.
Have a good w/e.!!