i scanned my harddrive. it took 2.5 hours! avira would make it in 40 minutes. and comodo even used 100% cpu while that.
while i looked at the scan progress, i noticed that the scanner jumps from partition to partition, and the back jumps are related to pk3 files. even while it is in a moment scanning the folder direct, many jumps appear to prior files back. it is not scanning continously, it is jumping mad (and i think it scans double).
the result is, that the scanned files got a number which is +150% of usual files scanned by normal antivirus programs.
this doesnt mean that comodo is very accurate, it means the opposite.
pk3 files are often used in quake 3 games and mods for example.
it doesnt look healthy to the harddrive.