View Full Version : Scratch Sizes, Ram, and Efficiency


Ed_L
10-19-2001, 01:35 PM
I need a little help understanding this. I'm running a PC with 256 megs of ram. When I have an image open and I view "efficiency" in the status bar, I sometimes get less than 100%. Doesn't this mean I am using the scratch disk? An example of one image shows 95% efficiency, and scratch sizes shows 60.3M/188.6M, while another shows 87% efficiency and scratch sizes shows 20M/188.6M. Yet another image might be much larger in file size, but efficiency shows 100%. I have one hard drive set up as my scratch disk, and it has 14.8 gigs free. Doesn't the first number indicate the amount of ram used for the image? I thought the second number indicated the size of the scratch disk available, but why does it only show 188.6 M?

Ed

DJ Dubovsky
10-19-2001, 01:52 PM
Ed,
I did a help search on Photoshop and here's what was written on Scratch size and efficiency.

Scratch Sizes- to display information on the amount of RAM and scratch disk used to process the image. The number on the left represents the amount of memory that is currently being used by the program to display all open images. The number on the right represents the total amount of RAM available for processing images.

Efficiency- to display the percentage of time actually doing an operation instead of reading or writing the scratch disk. If the value is below 100%, Photoshop is using the scratch disk and, therefore, is operating more slowly.

Hope this helps.
DJ

Ed_L
10-19-2001, 02:01 PM
Debbie,

Thanks for the information. Where did you find it? That clears up the "scratch sizes" issue. As per the "efficiency", I'm not sure if you can answer this, but I wonder why Photoshop would use the scratch disk when there is still plenty of ram to be used. My example above shows one image with efficiency at 87%, yet it is only using 20 megs of ram, while the others have higher efficiencies, but more ram is being used. Just doesn't make sense to me. There's only one image open at any time.

Ed

DJ Dubovsky
10-19-2001, 02:10 PM
Ed,
Maybe it has to do with how much of your RAM you have alloted to Photoshop. If you go to preferences > Memory & Cache you will see an area to assign Physical Memory Usage. It tells you your available RAm and you can allot a percentage to use. I have mine set at 60% right now but you could go higher if you wanted.

As to where I got the information, go to the help file and under index look for scratch sizes.
DJ

Ed_L
10-19-2001, 02:13 PM
Debbie,

I have my ram available for Photoshop set to 85%. I guess that's where the 188.6M come from in the scratch sizes information. I did a search on Photoshop too, but I didn't find much at all. Thanks again.

Ed

DJ Dubovsky
10-19-2001, 02:20 PM
Mine goes online and that I think was different than 5.0 or 5.5. You maxed out my answer potential Ed. Don't know why you're getting those readings for sure. Guess you will have to wait on a more experienced member to answer that.
DJ

Ed_L
10-19-2001, 02:23 PM
At least you got me straightened out on part of it. :) Thanks again.

Ed

kathleen
10-20-2001, 09:43 AM
hey ed

do pc's suffer from disc fragmentation, or is that just a mac problem? i think that can contribute in my system anyway, and running a utility to optimize the disk helped. you know what a computer guru i am;)

Ed_L
10-20-2001, 11:16 AM
Kathleen,

Pc's get the same old disease! But I doubt that's the problem because I can open one image right after another, and the same thing exists. But I just happened to defrag both hard drives last night, so when I get offline, I'll go back to check it out. If it's better, I'll let you know. It just doesn't make sense to me that one image would only use 20 megs of ram and run at 87% efficiency, while another would use 60 megs of ram and run at 94%. I sure wish somebody could explain that. Has anyone else seen this happen?

Ed

Ed_L
10-20-2001, 11:35 AM
You hit the mark square on Kathleen! That made a big difference. Thanks for the advice. Every so often, I have to shut down my computer manually, not being able to do it any other way (it freezes up). I'm sure that doesn't help with the fragmentation. Guess I'll have to defrag more often.

Ed

kathleen
10-20-2001, 11:51 AM
ed,

you can not imagine how that encourages me, to think i knew a computer answer. i can't believe it.

another thing i wondered about, don't know if this is mac-specific, but i think it doesn't happen in ps6, but does in 5 and 5.5 on macs, is automatic creation of "photoshop temp" files, which are invisible and huge and must eat up a lot of space. don't know what they're for, but now i reg. search for them "photoshop temp" and delete 'em

imagine that. imagine that. i am so pleased.

Ed_L
10-20-2001, 01:03 PM
Hey, turnabout's fair play. You made my day, and I made yours. :D I didn't find any temp files for Photoshop, so I don't know if it's Mac specific or not. Could be, I guess.

Ed

DJ Dubovsky
10-21-2001, 08:43 AM
Sounds like this is the "Guru" thread. :D Learning as we go, I like that.
JD

Doug Nelson
10-21-2001, 09:33 AM
All modern operating systems use a 'scratch disk' (aka: 'virtual memory'). If you don't specify a separate hd for Photoshop to use it simply uses the default virtual memory area.

If you have 2 or more physical hard drives you can assign both virtual memory and Photoshop scratch disk to the 2nd (ie: the non-booting hd). If you're uncomfortable foraging around in your OS's innards, I'd suggest simply pointing Photoshop to the 2nd hd.

This assumes a few things:
That your 2nd hd is fast and modern (as recently as 3 years ago hd speed increased enormously, and speeds up with every generation).
That your OS and Photoshop are on your boot drive (the idea is to separate your scratch area from your program area, doesn't do a lot if you just move them together).

Most ppl should simply leave the defaults. Some go so far as to use a utility to permanently commit a section (or 'partition') of a hd for virtual memory/scratch use, but we're talking serious techie here.

If you're really bothered by the reminder that you're not running at 100% (no one does) just click on the little right-pointing arrow next to that area and select a different display (I personally think the file sizes are a lot more relevant to display)

chris h
10-21-2001, 11:15 AM
Ed,

At least you've got the consolation that your PC doesn't run on petrol or diesel then you'd only be on 10% efficiency.

Did you do full defrag, how long to do it as regards time v disc capacity ?

When I defrag the drives its a case of letting the machine do it overnight.

jeaniesa
10-22-2001, 08:29 PM
Kathleen & Ed,

Photoshop definitely creates temp files on PCs - and they get VERY big!! Sometimes (I think when my computer crashes), they don't get cleaned up and I have to manually delete them. On my PC they're located in: Windows/Temp. You can't miss them if you sort the files by file size. ;)

Jeanie

Ed_L
10-22-2001, 08:46 PM
Thanks for all the replies. I wasn't aware that there more posts here. For some reason, I seem to be missing some of the new posts.

Chris,
I don't know how long it really takes, as I just do defrag overnight too.

Jeanie,
Thanks for the info. I'll have to check out my temp files there.

Doug,
I really never look at the efficiency. I guess that's why it bothered me when I saw it. Like you, I think the file size is more meaningful. Thanks for the lesson.

Ed

Roger Roberts
10-22-2001, 09:14 PM
Ed, I think if you copy (and paste) a large file, it stays in the clipboard until you copy something else or quit Photoshop therefore taking up that much ram that you can't use. You can gain that ram back by selecting a small area and copying,therefore pushing the large file out of the clipboard (thats what I read somewhere a long time ago and wish I could remember it when I'm working :) ).

Ed_L
10-22-2001, 09:31 PM
Roger,

I knew that something copied would stay on the clipboard, but I thought that after you pasted it, it would be cleared. Thanks for straightening me out on that. I'll try to remember that one.

Ed

DJ Dubovsky
10-23-2001, 08:51 AM
Ed
Go into your edit options (same place you assigned your avatar) and look for the thread options and choose show all threads. That will help so you don't miss them.
DJ

Ed_L
10-23-2001, 12:44 PM
Debbie,

I did that a long time ago. There are times when I get on the site, and have quite a few threads with new posts, only to have to get off for a while before reading all of them. When I do that, history is history. :( However, there are other times when I'm sure that all the new posts didn't show up. I've also had e-mail notices sent to me for all the threads, but it became more than I wanted to deal with. Thanks for the suggestion though.

Ed

chris h
10-24-2001, 05:54 AM
Ed,

I was told by my friend who works a lot with Photoshop that deselecting the options

Export Clipboard

Include composited Image


both found in preferences will save on memory and file space. The second creates files so the image can be used with older versions of the program.

CJ Swartz
10-24-2001, 03:03 PM
While working on a big image, I regain some of my RAM back by using Edit > Purge. Per the instruction book (see below), making snapshots or creating patterns uses RAM. I frequently practice on images that I've pasted into Photoshop from the web, and need to clear the clipboard.

C.J.

******************************************
Here's Photoshop's Help file on the Purge command:

The images and selections you cut or copy to the Clipboard or that you define as patterns or snapshots are stored in RAM. Keeping large amounts of data in RAM can significantly degrade Adobe Photoshop’s performance.

To clear cut and copied data from RAM:

Choose Edit > Purge and then choose an option from the submenu:

• Undo to remove from RAM a copy of the image before the last-performed operation.
• Clipboard to remove from RAM any data copied or cut from an image.
• Pattern to remove from RAM any defined patterns.

Note: To avoid filling the Clipboard with data, use the program’s drag-and-drop capability to drag elements (images, selections, channels, layers, and paths) from one file to another or from the Layers, Channels, or Paths palette to another file.

• Histories to delete all saved history information from all open documents. (You can also choose Clear History from the History palette menu to clear the history for the current document.)
• All to purge all of the items listed in the Purge menu.

Ed_L
10-24-2001, 03:17 PM
CJ and Chris,

Thanks much for the tips. That helps.

Ed