Mac updating boot caches
System cache files are generated by OS X and, unlike application cache, have nothing to do with the user.
The hidden system caches are mainly created by the apps that run on your Mac.
Be careful: not all app cache files can be safely deleted.
Some app developers keep important information on cache folders.
The clearing of system cache is not recommended in manual mode, unless you are very careful or trying to fix a problem.
System cache files do not generally take up much space, which is another reason why a clean out isn’t as necessary as with user cache.
User cache makes up the majority of junk data on mac OS.
Your applications accumulate user's cache data on a hard disk the longer they are in use.
Your Mac’s DNS cache is a list of all the DNS queries that were resolved for every site.Your Mac takes care of routine maintenance behind the scenes eventually, but that doesn’t mean you can’t keep things tidy yourself in the meantime.One easy way to keep your Mac running its best is to occasionally clean the cache.Sometimes it might help particular app performance, but usually it does not.If you don’t have a specific reason to clear Mac caches, don’t do it.