The problem with qBittorent

Hello! A couple of months ago I switched from utorrent to qbittorent, I couldn't get enough of it. Over time, I ran into a trail. problems:
1) During the distribution (it does not matter, fully downloaded or partially) a file, the consumption of RAM increases by 2 Gb, and this is observed some time after the client starts working, and not immediately after opening it.
2) If I put a speed limit on the upload of 1 KB / s, then the download speed immediately drops by 2 times. If I set a limit of 100 KB / s, the download speed does not change.
Can anyone come across the same and can I tweak something in the settings?
Or recommend another client.
Thanks.
P.S. Qbittorent version 3.2.5