Comment by neurostimulant

Does process substitution actually wrote the content to disk first or not? The information on internet I found seem to be conflicting on this. If it's actually writing the data into disk first, then it's probably won't solve my problem (limited disk i/o). Afaik writing to pipe won't result in saving the data to disk temporarily. I guess the only way to know is to try it out on my system and see how it performs.