You misunderstand. When RAM is 'full' the pagefile is used (pagefile.sys). A scratch disk is used for temporary files that an application uses during processing. Photoshop and other image processing applications make good use of scratch drives. Having temporary files on a separate scratch drive improves I/O performance (because only one I/O can be in progress to each drive at a time). A RAM drive is the fastest drive you can get, the downside is that it's volatile when the power goes off - and that makes it ideal for a scratch drive.I am slightly confused. If a scratch disk is used as an overflow when RAM is full, surely creating a scratch RAM disk won’t help in this situation, as you would just be swapping normal RAM for a RAM disk. Have I misunderstood?
I am slightly confused. If a scratch disk is used as an overflow when RAM is full, surely creating a scratch RAM disk won’t help in this situation, as you would just be swapping normal RAM for a RAM disk. Have I misunderstood?
I just want to clarify that memory (RAM) management is handled only by Windows and not by applications. The paging file (pagefile.sys) is used by Windows memory management to hold RAM pages that are not currently being used by any process. How pages get moved into the paging file (and back) and how RAM is managed when it's becoming exhausted is handled entirely by the Windows memory manager. There is a fairly detailed explanation of how WIndows manages RAM here: https://www.pcspecialist.co.uk/forums/threads/understanding-ram-management-and-use.60067/.Indeed, it depends on the reason for the scratch/cache disk. If it's for RAM overflow (basically video buffer) then it won't help. I think that's what @ubuysa was referring to when he stated the op has 64GB of RAM, there shouldn't really be a need for an overflow, it's just a nice to have. There are cases where it would even gobble up 64GB (4k editing with loads of effects)
The Scratch disk is used for other things as well though. Things that the software doesn't feel needs to go into the RAM as it's not efficient. When you're sitting on a project using 32GB of RAM with 32GB free and using stacks of files etc from all over the shop, a 10GB RAM disk as that cache/scratch would make a MASSIVE difference to any loading etc. I imagine this would be very useful in audio projects.