qBittorrent official forums

Hello,

I have been troubleshooting an issue for a while now and I am just stuck.

I had qbittorrent running perfectly fine through a vpn with port forwarding working then suddenly my download speed drops to zero. I had some upload speed working but no down. I tried restarting the client, I tried rebooting, I tried a different VPN server, I even tried a different VPN Provider. Nothing worked. My hdd is not full, but for the sake of testing, I even tried pointing to a different drive (ssd) and had no luck. This was on version 4.5.5.

I downgraded to version 4.3.9 and everything started working again! I even had crazy good download speeds. But after 5 minutes, everything drops to zero. If I restart qbit, it works again for only 5 minutes before dropping to zero. Also, when this happens, my whole computer gets really really slow. qbit and my vpn are the only things running. If I close qbit, everything speeds back up. I checked task manager and my CPU is under 60% and memory is under 30%. Idk why it's slow.

Some settings I have messed with

• Network interface -> VPN Interface

• Port used for incoming traffic -> port provided to me by vpn provider

• Peer connection protocol -> TCP and uTP

• Use UPnP/BAT-PMP port forwarding from my router -> is checked

• Outstanding memory when checking torrents -> 128 MiB

That is all I have really messed with. Any ideas?

Also, I am on Windows 10.

I'm having a very similar issue, my download speeds drop to 0 then shoot back up for a few seconds then drops back down again. So it's like it's bursting, I thought it was my nas drive starting to show it's age but it's happening with a new drive. If I try to close the program it tries to flush the downloads to the disk and hangs until I power off the drive.

Solution for the future people
I found out my problem. I realized, my HDD has a small cache. When qbit writes to the disk, it uses this cache which quickly fills up and once it does, all speeds drop to basically nothing. There might be some spikes but very short and with time between each one.

Your options are either buy a better hard drive with a much bigger cache, or set a max download rate. I played around with the latter for a while, trying different speeds. I found 9 MiB/s was the sweet spot. Anything higher, and I saw the cache fill up and speeds drop. Do the same for upload. I set my upload to 2 MiB/s. I didn't really mess with that one too much to find the best speed.

To check if your disk cache is full, on windows, go to task manager (ctrl + alt + delete), and go to the performance tab. On the left of the window, you will see the different disks. If the disk that qbit is writing to has 100% under the drive letter, then your cache is filled up. To clear it, just close qbit for a while. Monitor the task in process to make sure it fully closes. Try not to force kill the process as it takes a while to save the state of each and every torrent. Then you can re-open qbit, set those speed limits, and you should be golden.