I believe that there will be a delay the first time you run a new PAR executable, as it unpacks the contents to some temporary directories. I also believe that the temporary directories will still be there when you rerun.

In this case, I don't think your comparison is fair, unless you are noting a six second delay on second and subsequent activations.

Needless to say, housekeeping could remove the temporary files, and a new version of the .EXE will generate a complete new set of temporary files.

hth