[Cykon]

How much faster would Photoshop run on an Powerbook compared to an iBook? Are we talking minimally faster, moderately faster, or warp speed?

[cdsstan]

I have a 800 iBook. It's great for everything but when I use Photoshop is really bogs down. Sometimes I have to finish the image on my desktop dp500 G4, which flys in comparison. So the Powerbooks with their G4 CPUs and altivec engines should be alot faster than any iBook. If all you will be doing is Photoshop stuff, then the Powebook is for you. But if you're on a budget and require Photshop only some of the time, then the new 900 ibooks should be fine.

[SupahCoolX]

It really depends on a couple of things. First, are you talking an 867 or 1Ghz Powerbook?
Second, it depends what you do with it. If you're just doing basic stuff, and nothing too intensive, there won't be much of a difference. If you're running series of complex filters on 300MB files, then that's another matter. A similarly equipped (RAM, video card, etc) Powerbook would probably be moderately better.
www.xlr8yourmac.com and www.barefeats.com have lots of benchmarks you might want to look through.

[ccsccs7]

You also need to have a version of Photoshop and plugins that can take advantage of the G4 to benefit from the g4 processors in the Powerbooks.

[kovacs]

The difference in speed between the two is pretty big, but the biggest advantage of the powerbook is the bigger screen ( at least if you get the 15 inch or 17 inch powerbook ), believe me you can use every pixel you get...

I have a G3 and a G4, the speed is never a real problem the screen is !