what does it mean when it says

Scratch: 3.16G/1.63G

under the info palette?

This shows the size of the scratch disk that Photoshop has reserved at that time and how much it is actually using (if you check your designated scratch disk area you will see a Photoshop temp file with that size). This info at the bottom of the Info palette is the same info that is available in the staus bar at the bottom left corner of your Photoshop window. In the info window palette options in the context menu, you can choose what info you want displayed. You can also view the data in the status bar but only one option at a time.
Regards, Murray

This shows the size of the scratch disk that Photoshop has reserved at that time and how much it is actually using (if you check your designated scratch disk area you will see a Photoshop temp file with that size). This info at the bottom of the Info palette is the same info that is available in the staus bar at the bottom left corner of your Photoshop window. In the info window palette options in the context menu, you can choose what info you want displayed. You can also view the data in the status bar but only one option at a time.
Regards, Murray


thanks murray -- so for example X/Y, Y is the RAM i've allocated in the program's preferences, and X is the size of the scratch file.

how would i keep the scratch file size below that of the allocated ram? i did not assign a scratch disk on my system drive, but on 2 separate physical drives. and it doesn't seem to take much for the scratch file size to exceed the allocated ram. then things get slower than i'd like.

Scratch disk is NOT in RAM and has nothing to do with the % RAM you allocated to Photoshop in your preferences. It is the area of hard drive that you designated for Photoshop to use. There is no size to specify. If you did not designate a scratch disk, Photoshop will use whatever space it needs on the drive which contains your operating system (usually C Drive). It is better if you choose another physical drive if you have one because it will likely enhance Photoshop performance. You can actually watch what is going on with the scratch file by opening an image in Photoshop, add a layer or two, then go to your scratch disk and look for a file called Photoshop Tempxxxxx where xxxxx is a numerical number. If you check the size, it will be the same size as is shown in your info palette. When you close Photoshop down, it will erase the temp file which can get to several hundred megabytes in size. BTW, if Photoshop is closed due to a system crash or power failure, or program abort, then it will not delete that file. So every now and then it is a good idea to check your scratch drive to see if there are any residual such files as they can occupy a lot of space.
Regards, Murray

gotcha. but like i mentioned, i have 2 hard drives allocated just for photoshop scratch disks. i am not worried about losing space because of this. i also keep them defragged regularly with diskeeper.

i did see the temp files you were talking about.

so short of re-starting the program, is there anything else in the preferences i can do to keep photoshop running at optimum level?

i'm running a dual core machine with 4GB of ram in windows x64 off a raptor hard drive. 256MB graphics card.

2 additional hard drives for scratch disks.

a raid 10 array which i edit files on.

all drives have 16MB of cache.

i have 70% of RAM allocated to photoshop. no scratch disk assigned on the system drive. my cache levels are at 8, my history states are at 10, and i have bigger tiles enabled.

Looks like you are in great shape. The only thing you may find is that 10 History states is not enough. The default is 20 and I usually set mine to between 50 and 100 depending on the file I am working on and what I am doing. For example if you are brushing or cloning, your history will run out pretty quickly. Other than that you should be getting pretty good performance.
Regards, Murray