PSP X4, how much memory can be used?

[pinobot]

I have 8 GB of memory, in Help/About/System Info it says:

Memory Load Index 18 pcnt.
Total Physical Memory 655359 KB
Available Physical Memory 4,00 GB
Total Paging Memory 4,00 GB
Available Paging Memory 4,00 GB
Total Managed Memory 5 MB
Total Handles: 46
Temp Drive Free Space 202,75 GB

Is 4 GB physical memory the maximum PSP X4 uses or would installing more memory speed thing up.
I'm working with large panorama's with layers.

[df]

All 32 bit programs have the 4gb limit (or close to that). But that's not to say that having 8 or 16 gb on a 64 bit machine wouldn't speed things up since you could free up the entire 4gb to PSP and not have to share that with your OS and video card. There is a small program that can help. http://www.majorgeeks.com/CleanMem_d5993.html It uses Windows own memory management system to request back allocated memory from programs. It's different from other memory management programs as it doesn't just send the files to your cache (filling that up quicker), but instead just frees the RAM up to be used by any program. I first started using it with PSP X3 when it had the memory leak issue (resolved with a later patch). Basically if PSP says it has 4gb allocated to itself, then tries to open another layer that requests more memory, it will say that you're out of memory, even though it's not using all of the memory it has asked for. When I installed CleanMem I set it to run every 5 minutes and I never see a problem.