Hello, I am ordering a 1.33 GHz PB 15". I plan to add the 80GB 5400 RPM drive, not for the extra storage needs, but to increase speed of the machine. Can anyone explain whether this option truly makes sense to make an impact on daily performance tasks? Lot's of In Desigh to .PDF conversions, Illustrator work and Photoshop filtering going on daily for my use. Thanks!