This could happen if you have Photoshop’s RAM allocation set too high. The default 55% is about right for a system with up to 2GB of physical RAM.
Also look at setting the Windows paging file (Virtual Memory) to min=max=4GB
that’s what my allocation is set to.
Where do you find the windows paging file settings?
Open System Properties (Hold down WindowsKey, tap Pause/Break), then click Advanced tab>Performance Settings>Advanced tab>Change. Select a drive for the paging file, click Custom size, enter 4096 into both boxes, click Set, Okay, Okay, Okay. Okay? 🙂
Joe
For the non-techno’s amongst us could you kindly explain what exactly is ‘virtual memory’,what function it serves and with a scratch disk set up how does an increased vm improve performance?. I note from your advise to the OP that he should enter 4096 – is this a general rule – should one have the vm set at double the RAM capacity. Bye the way, have just checked my value and note that Windows has set a default of one and a half time my RAM value.
Alan, the word "virtual" means "almost real" (my own definition), and in the context of memory, it means using the disk drive as an extension to whatever amount of physical memory may be installed on the motherboard.
Note that the settings I mentioned in #4 relate to the virtual memory (paging file) used by the operating system (Windows).
Such VM allows Windows to "virtually" extend the amount of available RAM by spilling over into the paging file on the disk drive. If Windows lacked that capability, and your program needed more memory space, Windows would either have to tell you that not enough memory is available, or it would have to suspend another application, roll its allocated memory contents to a temporary file on the disk drive, and then give you that memory temporarily. When Windows again decided to turn control back to the other application (so it would not appear to be stalled), it would suspend your application, roll your allocated memory contents out to disk, reallocate the area to the other application, reload the first file back into that area, and finally, give control once again to the other application.
Because this can happen many times per second, all that thrashing slows things down tremendously because accessing data on a disk drive is hundreds of times slower than accessing physical memory. That’s why the existence of VM increases performance.
Regarding VM size, no number is sacred, but the general recommendation is to give Windows 1.5 to 2.0 times the amount of physical RAM for its virtual memory, or paging file. If the OP had 4GB or RAM instead of 2GB, I would have suggested following the general recommendation of using 1.5 times that, or 6GB, for the paging file.
You mixed the term "scratch disk" into your question. I assume you mean the VM that Photoshop uses, as defined in the Preferences window. (This VM is available only to Photoshop–it does not share it with Windows.) I understand that Photoshop does things differently, using the scratch areas first, resorting to RAM only when necessary. So, when it comes to scratch disk space, the more the merrier.
Joe
Many thanks for the WELL written and easy to understand explanation 🙂
deebs
thanks also, will have a read when time permits.
Happy to be of help, Alan. Maybe when solid state drives become available that are as fast as and as cheap as contemporary RAM, the overhead of swap files will go the way of the Osborne computer. For now, though, we have to live with them and try to understand them.