Why do the disk defaults minimise memory usage?

[Quitch]

So I'm looking at the Disk Cache settings and I'm wondering, why in a world where you won't find a machine shipping with less than 4GB of RAM, but hard drives still tend to be mechanical and the slowest part of the computer, is uTorrent set to minimise RAM usage at the expense of disk usage?

Even leaving only caching of reads and writes and increase automatic cache size when thrashing on, which if I understand correctly is the setup which should maximise memory usage, uTorrent doesn't seem to climb beyond 256MB of combined cache between reads and writes. It's not exactly a lot, so why is the program setup to try and keep usage even lower?

I'm sure it runs higher on really fat upload pipes, but honestly, how many users have that?

I feel either I'm missing something, or settings which might have made sense in 2005 could do with reviewing today.

[DreadWingKnight]

Why do you think that maximizing memory usage will increase performance to any noticeable degree?

[Quitch]

I don't know enough to know for sure that it will, and it's entirely possible that this is indeed the reason. However, given that the disk is the slowest part of a PC it seems that maximising disk reads and writes are putting additional pressure on the slowest part of the PC at a time when RAM is readily available.

In a world where RAM is readily available why default to trying to avoid using it?

[DreadWingKnight]

The thing is, outside of very specific circumstances, the hard drive is STILL transferring data both in and out faster than a torrent client can process it. With the larger piece sizes in torrents, pieces of 2mbyte+ are getting written in single operations.

With NCQ on hard drives, multiple pieces are getting written to the disk in a single rotation of the platters.

There's not enough benefit to even try to go pure ram in current setups.