BryanDowning
Joined: 05 Jul 2004
Posts: 1554
Location: California, USA
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 Posted: Sun Oct 07, 2007 9:30 pm Post subject: How Photoshop allocates RAM |
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Found this on an Adobe help page. This is VERY useful information to anybody who doesn't understand how Photoshop allocates RAM.
Source: http://kb.adobe.com/selfservice/viewContent.do?externalId=320005
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How Photoshop allocates RAM
When Photoshop starts, it allocates, or sets aside, a portion of RAM, the size of which is based on the amount that is designated in the Photoshop Memory & Image Cache preferences. While this RAM is reserved for Photoshop processes, it may be used by other applications when it isn't actively in use by Photoshop, and is released when you quit Photoshop. The default RAM allocation settings are 70% for Mac OS, and 55% for Windows. These settings should be optimal for most users. To get the ideal RAM allocation setting for your system, change the RAM allocation in 5% increments and watch the performance of Photoshop in the Performance Monitor (Windows) or the Activity Monitor (Mac OS). You must quit and restart Photoshop after each change to see the change take effect.
The available RAM shown in the Memory & Image Cache preferences already deducted an amount that is reserved for the OS at any given time from the total RAM in your machine. You shouldn't set the percentage of RAM to be used by Photoshop to 100%, because other applications which run at the same time as Photoshop (for example, Adobe Bridge) need a share of the available RAM. Some applications use more RAM than you might expect. For example, web browsers can use 20-30 MB of RAM, and music players can use 20-50 MB RAM. Watch the Performance Monitor or the Activity Monitor to view the RAM allocations on your computer.
Watch your efficiency indicator while you work in Photoshop to determine the amount of RAM you'll need to keep your images in RAM. The efficiency indicator is available from the pop-up menu on the status bar of your image and from the Palette Options on the Info Palette pop-up menu. When the efficiency indicator goes below 95-100%, you are using the scratch disk. If the efficiency is around 60%, you'll see a large performance increase by changing your RAM allocation or adding RAM.
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Best Regards,
Bryan Downing
bryandowning.com |
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