IO bound doesn't neccessarily mean waiting for GBs to transfer from the disk. It can mean reading meeelions of tiny files and seeking back and forth randomly. D

IO bound doesn't neccessarily mean waiting for GBs to transfer from the disk. It can mean reading meeelions of tiny files and seeking back and forth randomly. Doesn't matter if the files are in the cache or not. When someone says IO bound, it often means CPU bound but in the kernel or in some low level code. Most apps and games could open instantly, unless you are doing something like heavy map generation or hitting the network. But it would require structuring the app specifically for it and there is often no incentive to do so.