Scratch volume
Discussion
Being a computer novice, just come across this what I have not heard of before. I have installed Adobe Photoshop 7 and the following message came up.
You currently have AP7 primary scratch and window's primary paging file on the same volume, which can result in reduced performance. It is recommended that you set AP7 primary scratch volume to be on a different volume prferably on a different physical drive.
How do I do this? or is it best left alone?
Thanks,
Graham.
You currently have AP7 primary scratch and window's primary paging file on the same volume, which can result in reduced performance. It is recommended that you set AP7 primary scratch volume to be on a different volume prferably on a different physical drive.
How do I do this? or is it best left alone?
Thanks,
Graham.
I assume the "scratch volume" is just an area of disk space set aside for AP7 to use as virtual memory, so it doesn't have to go cap in hand to Windows every time it needs some.
As it'll be used heavily, it could well slow Windows down a bit, so moving it to a separate physical disk drive would be a good move.
Having said that, if you have just the one HD in your system its just tough; you'll have to live with it and ignore the message.
If you have 2+ disks, then moving it would be a good idea. Check the Help for instructions or look at Adobe's website.
As it'll be used heavily, it could well slow Windows down a bit, so moving it to a separate physical disk drive would be a good move.
Having said that, if you have just the one HD in your system its just tough; you'll have to live with it and ignore the message.
If you have 2+ disks, then moving it would be a good idea. Check the Help for instructions or look at Adobe's website.
The scratch disk is indeed a chunk of disk space that photoshop can use as it needs to when performing calculations related to an image you are processing. It will use the scratch disk when it runs out of RAM.
I can confirm that shifting the scratch disk to a physically separate drive does yield a performance increase. I have a separate SCSI disk just to use as a scratch disk.
If you can't run to a separate physical drive, then giving it a partition of its own on the single drive will yield some benefits, but be aware that scratch files can get quite big, even for seemingly small pictures.
To change where photoshop should use as a scratch disk, in PS7, click Edit > Preferences > Plug-Ins & Scratch Disks. From here nominate the appropriate disk, ok your way out and restart photoshop.
To monitor the the size of your scratch file, look on the status bar at the bottom of the screen for a right pointing triangle, somewhere to the left of centre. Click the triangle and select Scratch Sizes. The scratch size for open files will now be displayed to the left of the triangle with the number on the left showing how much memory is being used at the moment and the number on the right showing the total RAM available. I assume that when the number on the left is bigger than the number on the right then the system is using the scratch disk to supplement physical RAM.
>> Edited by arcturus on Wednesday 31st March 12:17
I can confirm that shifting the scratch disk to a physically separate drive does yield a performance increase. I have a separate SCSI disk just to use as a scratch disk.
If you can't run to a separate physical drive, then giving it a partition of its own on the single drive will yield some benefits, but be aware that scratch files can get quite big, even for seemingly small pictures.
To change where photoshop should use as a scratch disk, in PS7, click Edit > Preferences > Plug-Ins & Scratch Disks. From here nominate the appropriate disk, ok your way out and restart photoshop.
To monitor the the size of your scratch file, look on the status bar at the bottom of the screen for a right pointing triangle, somewhere to the left of centre. Click the triangle and select Scratch Sizes. The scratch size for open files will now be displayed to the left of the triangle with the number on the left showing how much memory is being used at the moment and the number on the right showing the total RAM available. I assume that when the number on the left is bigger than the number on the right then the system is using the scratch disk to supplement physical RAM.
>> Edited by arcturus on Wednesday 31st March 12:17
thornogson said:
Sounds like I could manage to do that, will it be alright to use an external hard disc as long as I have it coupled up when using AP7.
Thanks,
Graham.
Performance benefits could be insignificant or worse, if you use and external hdd with a slower connection than IDE.
Basically, ignore the warning message from Photoshop, when you do not have more than one drive on your computer's internal IDE controller. (read: you do not have two physical harddisks in your computer)
Seperate partitions on one disk won't help, because they're using the same IDE port, and hence won't allow parallel accesses to drives
>> Edited by Bodo on Wednesday 31st March 13:20
From my understanding, Photoshop uses the scratch area as it's workspace, but then uses RAM to cache this rather than simply paging to disk when it runs out of memory.
One benefit of having it on a different partition (even if you only have one drive) is that fragmentation of the scratch files are reduced, and is easily sorted by deleting and recreating the partition rather than defragging the whole drive.
Finally, as far as I know, it's better to have everything on one drive if this drive is faster than others on the PC. How much faster this has to be in order to outweigh the benefits of having it on a separate drive, I don't know...
One benefit of having it on a different partition (even if you only have one drive) is that fragmentation of the scratch files are reduced, and is easily sorted by deleting and recreating the partition rather than defragging the whole drive.
Finally, as far as I know, it's better to have everything on one drive if this drive is faster than others on the PC. How much faster this has to be in order to outweigh the benefits of having it on a separate drive, I don't know...
thornogson said:
thanks guys, good job you warned me about that. At present the hard disc is boot (C), backup (D), and recover (E) so if I put it on (D) that should be OK?
Depends whether those are (a) 3 seprate physical drives or (just as likely) (b) 3 partitions on one physical drive.
If (a) then go ahead. If (b) leave it as it is.
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