The very best part of your writing here is how you grab your reader's attention with a pressing question:
Is there any saving in disk space?At the same time, though your meaning is evident, the word saving in your first sentence doesn't sound quite so natural; in the second, it's OK. How about this instead? :
When saving your files, are you also looking to make the best use of disk space? -Then a file compression utility is just what you need. The saving of disk space is huge when you zip big files.
Student or Learner