I found and reported over a year ago about a Photoshop CS4 bug with respect to using 32GB memory. Photoshop CS4 for Mac allows less memory to be used with 32GB installed than with 8/16/24GB.
A year has passed since I first reported this issue to Adobe, yet the problem remains. That’s some customer commitment, a whiff of it anyway.
Guess what happens to Photoshop performance preferences when you install 24GB, 32GB, 48GB or 64GB memory?
With 24GB memory
The 3072MB figure is the maximum that CS4 allows to be specified. The “Ideal Range” is erroneous advice, another pimple that remains in place from years-old code.
With 32GB memory
With 32GB memory installed (eight 4gB modules), you’re allowed only 2810MB, 262MB less than with 32GB memory. The lower available memory can degrade CS4 performance.
With 48GB memory
With 48GB of memory installed, Photoshop restricts its memory usage to 902MB less than with 24GB! Yup, with twice the memory, you get to use 902MB less.
With 64GB memory
Even a blind squirrel finds an acorn once in a while: 3072MB again! Even the skeptical should now agree that there is a loose screw in CS4.