Once in a while I need to run a task that involves a lot of IO on the disk. Computationally it's not very intense, but it keeps having to hit my physical disk and files system every time.
For example, if I want to re-write the history of a git repository using
git filter-branch, run a code cleaner like
phpcbf over a massive project.
So I mount a tempfs (which is a very fast file system stored in RAM) (lets assume I only need 1G of RAM)
mount -o size=1G -t tmpfs none /mnt/tmpfs
Now simply put all your files into
/mnt/tmpfs as needed and enjoy.
This will disappear after reboot, so be careful to copy over what you need when you are done. There are tools such as Anything Sync Daemon to help with this