Memory and performance, Allocate ram to photoshop, Assigning scratch disks – Adobe Photoshop CS4 User Manual
Page 58: Change the scratch disk assignment
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USING PHOTOSHOP CS4
Workspace
Last updated 1/10/2010
The History Brush tool copies from one state or snapshot to another, but only at the same location. In Photoshop, you
can also paint with the Art History Brush tool to create special effects.
1
Select the History Brush tool
.
2
Do one of the following in the options bar:
•
Specify the opacity and blending mode.
•
Choose a brush and set brush options.
3
In the History panel, click the left column of the state or snapshot to be used as the source for the History Brush tool.
4
Drag to paint with the History Brush tool.
More Help topics
Paint with the Art History Brush
Memory and performance
Allocate RAM to Photoshop
Photoshop displays the RAM available to Photoshop and the ideal range of RAM for Photoshop (a percentage of the
total available RAM) in Performance preferences.
❖
In Performance preferences, enter the amount of RAM you want to allocate to Photoshop in the Let Photoshop Use
text box. Alternatively, drag the slider.
Assigning scratch disks
When your system does not have enough RAM to perform an operation, Photoshop uses a proprietary virtual memory
technology, also called scratch disks. A scratch disk is any drive or drive partition with free memory. By default,
Photoshop uses the hard drive on which the operating system is installed as the primary scratch disk.
Photoshop detects and displays all available internal disks in the Preferences panel. Using the Preferences panel, you
can enable other scratch disks to be used when the primary disk is full. Your primary scratch disk should be your fastest
hard disk; make sure it has plenty of defragmented
space available.
The following guidelines can help you assign scratch disks:
•
For best performance, scratch disks should be on a different drive than any large files you are editing.
•
Scratch disks should be on a different drive than the one your operating system uses for virtual memory.
•
RAID disks/disk arrays are good choices for dedicated scratch disk volumes.
•
Drives with scratch disks should be defragmented
regularly.
Change the scratch disk assignment
1
Do any of the following in the Scratch Disks area of Performance preferences:
•
To change the scratch disk order, click the arrow buttons.
•
To enable or disable a scratch disk, select or deselect the Active checkbox.