>How to Optimize Photoshop for Giant Images
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The inside story on how to get maximum performance from Photoshop when working on very large files, courtesy of Scott Byer from the Photoshop team.
You’ll want to look at the PDF in Adobe Acrobat, since OS X’s Preview app won’t render the text correctly. Conspiracy? 
Another tip is to check out Russel Brown’s scripts for Photoshop.
- Jonas