Many commercial scanners now let you set a system
resources option that will limit the virus scan from
consuming more than X% of the resources.
When my ClamWin scan kicks off on Monday morning, it
really drags my system down (and this is a recent AMD
Opteron processor with 512MB of memory) Yes, I have set
the Scanner Priority to 'Low' but it doesn't really
make much difference.
If the scanner Priority setting was meant to accomplish
this, then it doesn't seem to be doing much. But I
really liked McAfee's slider from 10-100% that you
could set. When that feature came out, it was huge for
the enterprise I supported since user always complained
about the load of virus scans - we set the slider to
20% or so and the users never knew virus scans were
happening after that.