PDHanumansvr is indeed converting all your clips loaded in your media room into smaller clips that can more easily be handled by PD. The result of the conversion remains in the folder ShowdowEditFiles until the retention period (as set in preferences) is passed, or until you (manually) delete the shadow files using the button in preferences, general to that effect. (Or delete the files directly in the (Windows) folder.)
Files in the media-room that have not been converted yet, show a little yellow icon in the left-hand bottom corner. Files that have been handled show a green icon.
Note that the shadow files may take considerable space on your disk depending on the editing work done and at hand.
I don’t think there is a difference in handling pre-cut files is regular clips.
The program indeed takes all the (CPU) power it can get, and the temperature can be high and the fans can make noise. Also obviously depending on the power available in your system. What I see in my systems is, that PDHanumansvr in most occasions modestly steps aside when another application needs CPU time.
I don’t think that changing the shadow file to a lower format will help, because it still requires conversion power. Turning the shadow file creation off, will help, but will also put an extra burden on your system while editing. You might see the editing work slowed down depending on the power of your system.
So far, apart from the fan sound, I have not seen any problems with this process. If it troubles you, you can of course change the settings to not make shadow files, or save the project and close PD for a while. Upon the start and loading of the project (and with the shadow files still in place) it will restart the conversion process where it left off).
The good thing is that converted files are there available for a bit smoother editing in PD.
So, there may be things you can do to minimize the overload. Or you may want to have look at the load of your system, when you do the PD editing, or look at whether the capacity of your system is suitable enough for the editing work you do.