script stresses system

I will run a script on a Windows XP PC against a file of MARC records
and it appears that the script significanly stresses my PC; the drive
light stays on, the fan runs continuously, it heats up,  For example a
script may run against a file of records by checking against another
file, and then writing the revised records out to a new file, and this
script may run several hours before completing.  Is there any way to
make the script less stressful, perhaps by pausing or hanging between
records, or after reading from or writing to disk?

Regards,

Mark