PPC G5 Dual 2.3 vs. MacPro Dual 2.66

Hey folks, need some input...

I own a portrait photography studio with about 13 Macs of varying styles (G4, G5, iMacs, etc) connected on a gigbit network.

Currently, my main graphic designer is using a PPC G5 Dual 2.3 with 8 Gb RAM. She uses Photoshop CS3 primarily, (and other assorted apps - but no video). She frequently works with files 20-600 Mb in size and experiences sluggishness and slow downs when re-sizing, transforming, saving, etc. (spinning beachball of death!) At another station we have a MacPro Dual 2.66 with only 2 Gb RAM that is the main download and editing computer. It is also the network hub computer for the studio with an external 6TB RTX server attached.

The problem: my designer needs better performance from her machine.... My question:
Do I upgrade the RAM in her PPC G5 machine to the max 16 GB? or do i switch out the machines, giving my designer the Intel MacPro, and then upgrade its RAM? Is there a HUGE difference in the performance of the processors between these machines or will the added RAM make up enough of the difference on the G5?

If the trade-out option is the best, that's okay, but it will require major time backing up systems and reformatting all of the drives, since they cannot just be swapped out. Not to mention reloading software, drivers, tools, etc. But does this risk compromising the speed of our studio network? since all of the other machines go through the MacPro to access the RTX server.....

i know this is a long winded question... any takers?

thanks

You should first realize that those 8 Gigs do not get used if all she's using is PS CS3. It can only use a max of 3-3.5 Gigs of RAM since it is a 32-Bit app so upgrading the G5 to 16 gigs would be useless. That being said make sure PS's preferences > performance has the ram upped to as much as possible. (Maybe its set for 1 gig max) The intel would be faster if you upped it to 4 gigs but don't go above that unless she uses more than just PS. Not until CS5 (CS4 for Windows) will Photoshop be 64-Bit and be able to handle 4+ gigs of ram. I have personally used PS CS3 with 4 gigs of RAM on a 2.4 Ghz Quad Core Vista machine with files as big as 2-3 gigs (.PSB files) so 600 Meg files shouldn't be too bad on that intel machine as long as you get it to 4 gigs.