Photoshop will ONLY use its scratch file as an auxillary paging space if YOU set the system paging space too small. As Photoshop is RAM humgry, even with 4Gb systems (system commit can be many multiples of real memory) having a system paging file BIG enough (as per Adobes recommendation, not your belief in how the Windows VMM works) is ESSENTIAL. Otherwise, the scratch file is used as a clipboard/image working space ONLY. Also, if you are using the Bigger Tiles plugins, real ram usage goes way up, thusly system page space usage goes way up as well. So if YOU deliberately set your system page space too small, YOU have caused Photoshop to page unnecessarilly to the PS/CS scratch file. And if PS has to use scratch space as paging space, it will also try to grow the scratch file to accomodate the new requirement. This, in conjunction with an overloaded page space, really kills hard drive performance as you now have a constant 4- or 5-way hit (program code, image data, page space, scratch spacex2) hit on a hard drive. Not too smart. It helps to actually know of what you speak.....