Will using an external FW HD as a scratch disk speed up Photoshop?

amin

macrumors 6502a
Original poster
Aug 17, 2003
977
9
Boston, MA
I have a spare FW 400 external drive lying around. Will using it as a PS scratch disk speed up my PS use? I can't yet afford to add a second HD to the Mac Pro I ordered today.
 

iMeowbot

macrumors G3
Aug 30, 2003
8,636
0
It might, if your main drive is busy doing other stuff. Why not plug it in and give it a try? It's easy enough to change it back if you aren't happy with the results.
 

YS2003

macrumors 68020
Dec 24, 2004
2,139
0
Finally I have arrived.....
seenew said:
How do you change your scratch disk?
What exactly IS the scratch disk/what does it do?
In Photoshop CS2's setting pane (Preferences--->Plug ins and Scratch disks). If your internal hd is not available for temporary usage by PS, you can assign the additional 3 scratch disk drives. PS stores active files temporarily on scratch disk so that you can keep working on PS. If there is not enough free HD space (ie. starving for the scratch disk space, I know PS will bog down (which happened to my old Ti PB as it only had 20GB before I upgraded it to 100 GB). Both of my Al PBs have 80 GB so I am not concerned about the scratch disk space (I store files on the external HDs). Even my iBook with 40 GB (19.5 GB free) is managing PS without scratch disk space problems.
 

spicyapple

macrumors 68000
Jul 20, 2006
1,725
0
Firewire HDs are slow. You're better off moving unused files from your internal to the fw hd and using the internal as the scratch disk.
 

iMeowbot

macrumors G3
Aug 30, 2003
8,636
0
seenew said:
What exactly IS the scratch disk/what does it do?
As of CS2, it's really an undo buffer. In past versions, it was a weird attempt to duplicate what virtual memory does.

Adobe offer a long discussion of how real memory, VM, and scratch are used. For interactive PS work, scratch disk speed only really becomes important if you use batch processing (actions) or have too little memory.