Visual Patch Compression

I've noticed that the resulting patch size is consistenly quite large. For example I have two versions of the product, version 1.0 and version 1.1. The projects themselves are each about 14 MB. If I ZIP compress the entire project the size of the restultant zip file is about 6 MB. Not all of the files in the release have changed, yet when I create a new patch file the resultant patch file is 8.5 MB. Is there some way to optimally minimize the size of the resultant patch file?

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