Photoshop & RAM

[smokingpopsicle]

I heard that Photoshop CS can only support up to 2 Gigs of RAM. I have a G5 that can be upgraded to a maximum of 8 Gigs I believe. So what happens to any extra RAM? Would having over 2 Gigs of RAM be of any benefit to me?

[almaink]

Yes the system will use the extra ram and you will be able to multitask by having other apps open at the same time as PS.

[Screamingbeaver]

I've read some stuff about Photoshop and Ram in MacAddict. Check out his article...

http://www.macaddict.com/issues/0312/rev.g5.html

I read that there was a huge boost from 512meg to 1Gig, however once you hit 3gig of Ram there really wasn't any performance increase. I can't remember where I read that. Maybe MacWorld...

Later,
Beaver

[Sparky]

I know there is a myth about more RAM is better, but in the days of OS 9 and earlier, the rule of thumb was to have 3 times as much RAM allocated to Photoshop as the file size you intend to work with. Reason being is that the file needs to be stored in the buffer memory and each time you perform a task and "save" the entire file needs to be rewritten first to a scratch disk then back to the buffer. So you have the original file = 300mb plus the buffer size =300mb and the scratch disk (where the file is temporaily written as a save is done) =300mb hence if you work on files that are 300 mbs in size you would want to have at least 900mb or 1gb of RAM aloocated for Photoshop to work as efficiently as possible. Any more was a waste of RAM as the program never accessed it.

That said and knowing that in OS 10.x you can only specify the % of available RAM any program can use I would just keep Photoshop at about 25% if you have 8gb of RAM. any more would be wasted and not allow other programs to access it.

[matmac]

At the bottom of the image window in Photoshop it is possible to set the fly-out menu to "Efficiency".



This is a displays the amount of processing that Photoshop is doing in RAM. 100% is ideal, if the figure starts to drop below 75%, you will notice a significant performance slump.

Turn this guy on and monitor the % figure, if it frequently drops from 100%, it might be time to allocate more Ram to Photoshop.

When Photoshop runs out of Ram to perform operations, it moves to writing data to/from the Hard Drive. This is known in Photoshop as a "Scratch Disk". Scratch Disks are configured through the Preferences in Photoshop. (Photoshop CS allows for up to 4 different disks (partitions) to be nominated.)

For optimal performance in PS, create a separate partition on your HD and call it "Scratch" (or similar) nominate this as the primary Scratch partition. Using the default startup disk for PS results in poor performance as the boot disk is usually fragmented. (This may be different under MacOS 10.x but is certainly the case under 9.x)
Having a separate partition with no files on it means that there is no fragmentation on the drive.
Better still is if the Drive can run on a separate controller. (ATA or SCSI).

Given the increased levels of Ram that the Mac platform now supports, scratch disks are becoming more irrelevant, as a 200MB file needs 3-5x that in Ram (1GB). Which the Mac may very well have.

[Sparky]

Originally Posted by almaink

Yes the system will use the extra ram and you will be able to multitask by having other apps open at the same time as PS.

If you have 4gb of RAM, Photoshop may only handle up to 2gb but when you have InDesign open (128mb minimum to run) and the OS (anywhere between 50mb and 256 or higher mb) then open Illustrator and crunch a 300mb file, I think you will see the benefits of having as much RAM as possible. So by having the space for 8gb RAM you allow yourself to play with 600mb files in Photoshop while listening to iTunes on your headphones and creating a 64 page 7/color catalog in InDesgin all at the same time and never see a slow down :lol: :lol: :lol:

[jim_t]

For the most optimum use of your G5 a scratch disk partition in conjunction with a hefty amout of Ram will be a great combination. The only other area that most users forget is that there is an update that optimizes the use of the G5 processor in photoshop. If you are on a G4 once again the scratch disk partition will help big time with both Illustrator and Photoshop. 1gb should be plenty enough but with the drive sizes today I've usually give 2.