Hi
I have a 3ghz Pentium4 with 2GB DDR & 160GB HDD which I only really use for Photoshop CS2. I've noticed it can run a bit slow with bigger Photoshop files (70MB+) which I'm a bit surprised at considering there's 1.5G of RAM allocated to the program. The strangest thing is when I checked the 'Scratch size' at the bottom of the document, I noticed that the RAM usage of an 87MB file went from 361MB to a massive 1.24GB with just a few slight changes to the file. I understand that the RAM usage would probably increase due to actions being added to the 'History' but surely not by that much??! I had upgraded the RAM recently so I tried putting back the original 2x512DDR to see if it sorted the problem but I'm still getting extortionate RAM usage...
Does anybody know the typical 'Scratch size' in relation to file size on a computer similar to mine?
(If it's any use the file was an 8bit RGB, 600dpi at 3031x4571 pixels).
I'd appreciate any help or advice.
Dan

Dan--I'm afraid I can't answer your question directly (I could tell you about scratch disk size in relation to your page file size...but that wasn't your question! ;-))...but I can point you towards this article, which might give you some more insight into the question...as well as point out a few tweaks you can make to get Photoshop running more quickly. (The article is for CS2, but I've used most of them for CS, just fine...) http://www.adobe.com/support/techdocs/332271.html

Two things that do occur to me right away are: a) that it sounds like your scratch disk is on the same drive as Photoshop (performance can REALLY improve if you give Photoshop it's own separate hard drive for it's scratch disk...or, barring that, you'll even see some performance increase by having it on the same hard drive--but on a separate partition...and b) you didn't mention when was the last time you defragged. (If you haven't in a while--you should. Try downloading a trial version of Diskeeper, and run it--it's much more efficient than Windows' own tool for the job. You might find this to be a significant help to you.

Oh--and also, how much free space do you have on your hard drive (160gb is pretty small these days, if you leave your Photoshop images on the hard drive!)? Do you actually have sufficient room for your page file (which, hopefully, you have set to the same minimum and maximum, so your system isn't constantly resizing it) AND your scratch disk space? (Again--these are related to speed and performance, rather than size, so they're sort of tangenital to your question...but they're good things to think about, if you're not, already! ;) And the article I pointed you towards DOES address the sorts of changes you can make to your file that cause extra resource drain...)

Good luck with this--and hopefully someone else will chime in, with more info for you--

I dedicate a separate 50gig partition to Photoshop for a scratch disk. I know that's a lot, but I've got hard drive space to spare.

Well...if ya got it...flaunt it, Baby! Oh, wait...we're talking about scratch disks, right? ;)

I've actually done the same thing before...just tossed an old 80GB drive in an extra bay, and gave the whole thing to Photoshop. Why not, right? :)

Partitioniong a single drive as a scratch disk is of little to no value, because the OS resides on the disk and no matter how much RAM you have Photoshop writes to disk. A second 7200 RPM drive or faster should be installed and assigned in Photoshop preferences as a scratch disk. 4x maximum file size is sufficient for scratch disk space. I partioned my 50G 7200 RPM Seagate Barracuda at 10x for the first partition and use the balance in a second partition for file storage. A fast Firewire external drive would be an alternative if you can't install an internal drive...jf

And if you're in the mood for more reading...this is a pretty comprehensive "nuts and bolts" explanation of scratch disk usage: http://www.macgurus.com/guides/photoshopguide.php (scroll down to the several scratch disk tips)

Hi
Thanks for taking the time out to reply :) your help was really useful. It sounds like I'd benefit from an additional hard drive assigned solely to the primary scratch disk, so I've decided to purchase one. By default, my primary scratch disk has always been set to Startup with no secondary scratch disk in place - is this right? Also, if I do need to partition some space on the hard drive how would I go about doing so? You'll have to excuse my ignorance - my computer knowledge is a bit limited.
Thanks
Dan

Sorry I can't help you partition on a PC, I don't know the OS but include a link below. Yes, you will have to reassign the newly install disk as scratch disk in Photoshop. I buy my HD's at newegg.com, but sometimes you can find great blowout rebate deals at CompUSA etc. Remember 7200 RPM...skip

http://support.microsoft.com/?kbid=313348

Thanks for the link Skip - it was a great help :)

I put a separate partion for photoshop scratch disk on a second internal hard drive, and a second on its own partion on the main drive in case photoshop needs more.
also try putting a separate partion on the second hard drive for windows virtual memory.
I have an older P4 1.6G with only 512MB of ram and it can handle over 100mb files with layers (my wife does digital scrapbooking which can have many layers) without too much of a problem.
follow the link below on the recommendations from adobe.
turn off max compatability in preferences as well.

hope this helps