qBittorrent official forums

qBitTorrent's (libtorrent's actually) cache is wasteful -- for every 100 MB of additional cache size, qBitTorrent uses over 130 MB ram.

qBitTorrent crashes if its ram usage is over ~1950 MB (for the 32 bit version):
index.php/topic,2042.0.html

This can happen even with default settings at very high download and/or upload speeds:
index.php/topic,3567.msg17758.html#msg17758

The 64 bit version of qBitTorrent can handle a cache size as large as 4096 MB (4 GB), but qBT's extremely poor memory management can waste >1 GB extra and use >5 GB of ram.
There isn't really any reason to set the cache that high, because it won't help if the disk overload is due to slow drives -- it will delay the overload but make it much worse when it happens.
Best to not set qBT's cache size over 1000 MB regardless of using 32 or 64 bit qBT.

A long standing problem with bittorrent clients on windows is that if you’re seeding large files or downloading large files, windows may decide to essentially use all your physical RAM for disk cache. The disk cache grows to the point where running processes start having their working set swapped out, significantly slowing down the system as a whole. Both uTorrent and libtorrent based clients have this problem.

http://blog.libtorrent.org/2012/05/windows-disk-cache/

Well, as you can see, i don't seed nor download large files. Or are these 300MB files considered large?
Nevertheless, i don't remember utorrent (3.2.1) ever consuming more than 100MB in my use case.

I see nothing (image is not loading), or did you mentioned that you are downloading that size of files.

Its always good to restart the client now and then after that long sessions.

Also I would advice to disable OS cache in advanced settings if you are seeding only.

It is loading for me, but ok, i attach it here too.
And yes, i know, restart helps. But if it's possible i prefer not to restart applications but to point out potential memory leaks which may affect everybody.

"Enable OS cache" is unchecked.

Thanks, I get the following to see at your previous picture (attachment).

Try with disabling OS cache and see how it goes.

[quote="diaspar"]
Well, as you can see, i don't seed nor download large files. Or are these 300MB files considered large?
[/quote]
It is nothing to do with file 'size', BitTorrent clients do not cache or download entire 'files', downloads and uploads are done in 16kiB blocks.