Photoshop on a Mac - do I need a scratch disc?

[Robert Wilde]

I just received my 2.16 ghz 24" iMac (I got myself a white 24" iMac because of the matte screen and the great graphics card, the nVidia 7300GT, which you also find in the MacPro).

Now I read, that many users of Photoshop set up a scratch disk as an extension to their RAM.

I put in the maximum RAM of 3Gb.

Do I still need a scratch disk? And if yes, what would your recommend?

I am very much into a silent computer, and would not really enjoy a noisy Raptor or other high spinning disk...

[AndrewRodney]

Photoshop needs 3-5X file size in ram OR HD. So it depends on the file size (layers count). So yes, its possible you'll hit scratch disk. IF you only have one drive, it uses free space there. At the bottom of the document, you can select Efficiently to see where you stand with that document.

[BobSmith]

Originally Posted by Robert Wilde

I am very much into a silent computer, and would not really enjoy a noisy Raptor or other high spinning disk...

Same here. I use a 20" iMac with an additional 20" Cinema Display for exactly that reason. It's connected via gigabit ethernet to a server loaded with drives happily humming away in a closet at the back of the building. The workstation area is VERY quiet. Depending on the way you use Photoshop you may be perfectly content using scratch space on the internal drive. If you feel the need for more speed use the firewire connector to hook up a single external drive and choose one of the fanless single drive cases. There's a number of them on the market that are good. I have one by Wiebetech. Its connected to the iMac via Firewire but sits in a cabinet below my desk. It's in a large enough space for ample cooling but adds almost zero noise to the work environment.

Bob Smith

[AngelMorales]

Hey,
Any good external drive will most certainly do the trick. I also use WEibetech. They are quiet, but really nothing special, as they are just Seagate drives in the shell. You are really paying for the shell. There are other cheaper alternatives. You can buy a shell from other manufacturer and install a Seagate or Western Digital drive or other, for almost no cost.
Angel

[Jerry Skrocki]

Adding an external firewire or usb drive for use as a scratch disk on an iMac is going to slow down Photoshop performance. The scratch disk should be placed on the system's fastest drive and in the case of an iMac, it is the internal drive. While an external hard drive is great for backup and storage, it cannot compete with the performance of the internal drive.

Your best bet is to use the internal drive as scratch disk.

[Robert Wilde]

Originally Posted by BobSmith

Same here. I use a 20" iMac with an additional 20" Cinema Display for exactly that reason. It's connected via gigabit ethernet to a server loaded with drives happily humming away in a closet at the back of the building. The workstation area is VERY quiet. Depending on the way you use Photoshop you may be perfectly content using scratch space on the internal drive. If you feel the need for more speed use the firewire connector to hook up a single external drive and choose one of the fanless single drive cases.

Bob Smith

The closet idea is great! Somewhere in the future I might be getting a MacPro, I also consider to get the machine out of the work area, so there would be no ventilator noise, just the birds from the garden.

[Robert Wilde]

Originally Posted by Jerry Skrocki

Adding an external firewire or usb drive for use as a scratch disk on an iMac is going to slow down Photoshop performance. The scratch disk should be placed on the system's fastest drive and in the case of an iMac, it is the internal drive. While an external hard drive is great for backup and storage, it cannot compete with the performance of the internal drive.

Your best bet is to use the internal drive as scratch disk.

An USB drive is definitely slow.

Regarding the firewire drive, we have opposing statements here. Bob Smith mentioned, using a firewire disc would be faster than using the internal hard drive, and you said it was the other way round.

Maybe we could clear that up?

Possible you were talking about different firewire speeds? I have Firewire 800, which is much faster than 400, and use a g-tech Q Drive external hard drive (hitachi drive inside, and here, too, you pay premium for the reliable enclosure).