More Cache = ???

Sooo, i was just wondering how more Cache can actually benefit your computer, other than lowering access times.
But really, what is it used to access? what kind of data, and is there some kind of way to set cache on some sort of data, to shorten its load time, dunno if thats possible

For regular HDDs, the cache size doesn't really change alot. For SSDs it may have more influence since the DRAM cache acts as buffer, queueing up I/O that needs to be done.

For normal uses a read cache on the disk is useless. Modern systems have 4GB memory so have a 3.5GB file cache in reality. So what is 16MB or 32MB compared to 3.5GB? Let your OS cache files for you. The HDD actually just needs a tiny buffer to queue I/O, which is especially important for writing. Writing without buffer is very slow (1MB/s). And SSD's without DRAM memory chip are very slow too also because they can't buffer the I/O.

So i would say, get more RAM instead of a HDD with more cache.