I started to notice some performance problems on the SSD drive that host the cache dir with the high average response time on the drive, but nothing being writen\read massively. Other times I get high average response times but 120mb\s writing or reading which is normal
Regarding torrents i completely understand, however it does not explain the high response time from the SSD disk, and when that happens, the activity on torrent client drops to near 0 kbps
I completely understand that option, however I am trying to understand with people around here if there's not a problem with vfs implementation, because even if the cache is being hit hard, that does not show on resource monitor like the screenshot i just attached. the disk was overloaded with 100% and was only touching apparently 3 files with less then 1mb\s being read.
By this behavior, even if the cache was being "hit hard" we would see different behaviors on read and write speeds, especially when we are talking about an SSD.
This is a USB SSD drive, it may not support TRIM or other advanced features. Are you connected with USB 3.x? Also, you show that you are running Windows 8.1, is that correct? Try using a benchmark tool like crystaldiskmark to see what the upper end of performance for this device is really like. Then compare that to what you are seeing with rclone.
If you are seeing poor performance with crystaldiskmark, then I think you need to look to see if there are any driver or firmware updates to your system.