Why does the 32-bit CS5 Limit memory to 2100MB? This is like purchasing a Ferrari
and then being told you can only drive it in the parking lot.
This basically causes me to keep cs4 running until all my plugins have been converted to 64bit.
You can see previous discussions, but the jist of it is this: Photoshop and the OS need more RAM under Cocoa, so the amount of available memory is reduced. Not much we can do about it, sorry.