Scratch Sizes, Ram, and Efficiency

Ed_L · #1 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 · #2 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 · #3 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 · #4 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 · #5 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 · #6 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 · #7 10-19-2001, 02:23 PM

At least you got me straightened out on part of it.

Thanks again.

Ed

kathleen · #8 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 · #9 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 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 · #11 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 · #12 10-20-2001, 01:03 PM

Hey, turnabout's fair play. You made my day, and I made yours.

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 · #13 10-21-2001, 08:43 AM

Sounds like this is the "Guru" thread.

Learning as we go, I like that.
JD

Doug Nelson · #14 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 · #15 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.