DL speed randomly collapses

[TheHellSite]

qBittorrent version and Operating System

Linux DOWNLOAD-VM 4.19.0-12-amd64 #1 SMP Debian 4.19.152-1 (2020-10-18) x86_64 GNU/Linux
qBittorrent v4.2.0 and v4.3.0
Flatpak v1.2.5-0+deb10u1

If on linux, libtorrent-rasterbar and Qt version

latest flatpak stable package of qBittorrent

What is the problem

As the title says I am having some trouble with my DL speeds in qBittorrent (v4.3.0) running alongside pyLoad in my download vm. The whole traffic of that vm gets tunnelled trough my vpn provider. A set a static torrent port in qBittorrent and forwarded that port at my vpn provider and in my firewall to the download-vm. The port also gets recognized as open. Both qBittorrent and pyLoad download to my nas with an smb share that is mounted to a local directory.

Sometimes my torrent files run just fine at full speed (~6 MB/s). But most of the time the download starts, goes to full speed and then all of a sudden the speed goes down to around 10 KB/s. I doesn't happen at a specific DL size, time or percentage.

What makes me believe that it has to do with just qBittorrent is the fact that pyLoad and a speedtest run at full speed while the torrent speed is slow.

After restarting qBittorrent, while the torrents are still running, the speed goes back to normal.

What is the expected behavior

full speed

Steps to reproduce

none

Extra info(if any)

It doesn't have to do anything with the flatpak package of qBittorrent.
I tested the flatpak version and the "apt" version of qBittorrent. Both have the same error.

qBittorrent.conf

[Application]
FileLogger\Age=1
FileLogger\AgeType=1
FileLogger\Backup=true
FileLogger\DeleteOld=true
FileLogger\Enabled=false
FileLogger\MaxSizeBytes=66560
FileLogger\Path=/home/###/.var/app/org.qbittorrent.qBittorrent/data/qBittorrent/logs

[AutoRun]
enabled=false
program=

[BitTorrent]
Session\BTProtocol=TCP
Session\DisableAutoTMMByDefault=false
Session\DisableAutoTMMTriggers\CategorySavePathChanged=false
Session\DisableAutoTMMTriggers\DefaultSavePathChanged=false
Session\MultiConnectionsPerIp=true
Session\SlowTorrentsDownloadRate=100

[GUI]
DownloadTrackerFavicon=true
Log\Enabled=false
Notifications\Enabled=false
Notifications\TorrentAdded=false

[LegalNotice]
Accepted=true

[MainWindow]
geometry=@ByteArray(\x1\xd9\xd0\xcb\0\x3\0\0\0\0\0\0\0\0\0\x1f\0\0\x3\xfb\0\0\x2\xfd\0\0\0\0\0\0\0<\0\0\x3\xfb\0\0\x2\xfd\0\0\0\0\x2\0\0\0\x3\xfc\0\0\0\0\0\0\0<\0\0\x3\xfb\0\0\x2\xfd)
qt5\vsplitterState=@ByteArray(\0\0\0\xff\0\0\0\x1\0\0\0\x2\0\0\0x\0\0\x2\x16\x1\xff\xff\xff\xff\x1\0\0\0\x1\0)

[Network]
Cookies="__cfduid=d2f3fd16c4d1abd2d3a0ff21d7a475cc91604278489; HttpOnly; expires=Wed, 02-Dec-2020 00:54:49 GMT; domain=.db-ip.com; path=/"

[Preferences]
Advanced\AnonymousMode=true
Advanced\DisableRecursiveDownload=false
Advanced\IgnoreLimitsLAN=true
Advanced\IncludeOverhead=false
Advanced\RecheckOnCompletion=true
Advanced\TrayIconStyle=0
Advanced\confirmRemoveAllTags=true
Advanced\confirmTorrentDeletion=true
Advanced\confirmTorrentRecheck=true
Advanced\trackerPort=9000
Advanced\useSystemIconTheme=true
Bittorrent\LSD=false
Bittorrent\MaxRatio=1
Bittorrent\MaxRatioAction=1
Connection\GlobalDLLimitAlt=500
Connection\GlobalUPLimit=2048
Connection\GlobalUPLimitAlt=500
Connection\Interface=###
Connection\InterfaceAddress=###
Connection\InterfaceName=###
Connection\PortRangeMin=###
Connection\ResolvePeerCountries=true
Connection\ResolvePeerHostNames=false
Connection\UPnP=false
Downloads\DblClOnTorDl=0
Downloads\DblClOnTorFn=1
Downloads\NewAdditionDialog=true
Downloads\NewAdditionDialogFront=true
Downloads\PreAllocation=true
Downloads\SavePath=/mnt/nas/download/
Downloads\ScanDirsV2=@Variant(\0\0\0\x1c\0\0\0\0)
Downloads\UseIncompleteExtension=true
DynDNS\DomainName=changeme.dyndns.org
DynDNS\Enabled=false
DynDNS\Password=
DynDNS\Service=0
DynDNS\Username=
General\AlternatingRowColors=true
General\CloseToTray=true
General\CustomUIThemePath=
General\ExitConfirm=true
General\HideZeroComboValues=0
General\HideZeroValues=false
General\Locale=en_GB
General\MinimizeToTray=true
General\MinimizeToTrayNotified=true
General\NoSplashScreen=true
General\PreventFromSuspendWhenDownloading=false
General\PreventFromSuspendWhenSeeding=false
General\StartMinimized=true
General\SystrayEnabled=true
General\UseCustomUITheme=false
MailNotification\email=
MailNotification\enabled=false
MailNotification\password=
MailNotification\req_auth=false
MailNotification\req_ssl=false
MailNotification\[email protected]
MailNotification\smtp_server=smtp.changeme.com
MailNotification\username=
Queueing\IgnoreSlowTorrents=true
Queueing\MaxActiveDownloads=-1
Queueing\MaxActiveTorrents=-1
Queueing\MaxActiveUploads=2
Queueing\QueueingEnabled=true
Scheduler\days=0
Scheduler\end_time=@Variant(\0\0\0\xf\x4J\xa2\0)
Scheduler\start_time=@Variant(\0\0\0\xf\x1\xb7t\0)
State\hSplitterSizes=123, 630
State\size=@Size(779 591)
WebUI\Address=###
WebUI\AlternativeUIEnabled=false
WebUI\AuthSubnetWhitelistEnabled=false
WebUI\BanDuration=3600
WebUI\CSRFProtection=true
WebUI\ClickjackingProtection=true
WebUI\CustomHTTPHeaders=
WebUI\CustomHTTPHeadersEnabled=false
WebUI\Enabled=true
WebUI\HTTPS\CertificatePath=###
WebUI\HTTPS\Enabled=true
WebUI\HTTPS\KeyPath=###
WebUI\HostHeaderValidation=true
WebUI\LocalHostAuth=true
WebUI\MaxAuthenticationFailCount=0
WebUI\Password_PBKDF2="###"
WebUI\Port=###
WebUI\RootFolder=
WebUI\SecureCookie=true
WebUI\ServerDomains=*
WebUI\SessionTimeout=3600
WebUI\UseUPnP=false
WebUI\Username=###

[RSS]
AutoDownloader\DownloadRepacks=true
AutoDownloader\SmartEpisodeFilter=s(\\d+)e(\\d+), (\\d+)x(\\d+), "(\\d{4}[.\\-]\\d{1,2}[.\\-]\\d{1,2})", "(\\d{1,2}[.\\-]\\d{1,2}[.\\-]\\d{4})"

[ShutdownConfirmDlg]
DontConfirmAutoExit=false

[SpeedWidget]
Enabled=true
graph_enable_0=true
graph_enable_1=true
graph_enable_2=false
graph_enable_3=false
graph_enable_4=false
graph_enable_5=false
graph_enable_6=false
graph_enable_7=false
graph_enable_8=false
graph_enable_9=false
period=1

[TorrentProperties]
CurrentTab=0
Peers\qt5\PeerListState=@ByteArray(\0\0\0\xff\0\0\0\0\0\0\0\x1\0\0\0\x1\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\xe\0 \0\0\0\x1\0\0\0\r\0\0\0\x64\0\0\x5\x14\0\0\0\xe\x1\x1\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x64\xff\xff\xff\xff\0\0\0\x81\0\0\0\0\0\0\0\xe\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\x3\xe8\0\xff\xff\xff\xff)
SplitterSizes="181,429"
Trackers\qt5\TrackerListState=@ByteArray(\0\0\0\xff\0\0\0\0\0\0\0\x1\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x3 \0\0\0\b\x1\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x64\xff\xff\xff\xff\0\0\0\x81\0\0\0\0\0\0\0\b\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\x3\xe8\0\0\0\0\x64)
Visible=true
qt5\FilesListState=@ByteArray(\0\0\0\xff\0\0\0\0\0\0\0\x1\0\0\0\x1\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x2X\0\0\0\x6\x1\x1\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x64\xff\xff\xff\xff\0\0\0\x81\0\0\0\0\0\0\0\x6\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\x3\xe8\0\xff\xff\xff\xff)

[TransferList]
qt5\HeaderState=@ByteArray(\0\0\0\xff\0\0\0\0\0\0\0\x1\0\0\0\x1\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1f\b\xc0\xff?\0\0\0\x11\0\0\0\x18\0\0\0\x64\0\0\0\x19\0\0\0\x64\0\0\0\x1a\0\0\0\x64\0\0\0\x1b\0\0\0\x64\0\0\0\x1c\0\0\0\x64\0\0\0\x1d\0\0\0\x64\0\0\0\xe\0\0\0\x64\0\0\0\xf\0\0\0\x64\0\0\0\x10\0\0\0\x64\0\0\0\x11\0\0\0\x64\0\0\0\x12\0\0\0\x64\0\0\0\x13\0\0\0\x64\0\0\0\x3\0\0\0\x64\0\0\0\x14\0\0\0\x64\0\0\0\x15\0\0\0\x64\0\0\0\x16\0\0\0\x64\0\0\0\x17\0\0\0\x64\0\0\x5x\0\0\0\x1f\x1\x1\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x64\xff\xff\xff\xff\0\0\0\x81\0\0\0\0\0\0\0\x1f\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\0\0\0\0\0\x1\0\0\0\0\0\0\0\x64\0\0\0\x1\0\0\0\0\0\0\x3\xe8\0\0\0\0\x64)

[TransferListFilters]
selectedFilterIndex=0

[thalieht]

What makes me believe that it has to do with just qBittorrent is the fact that pyLoad and a speedtest run at full speed while the torrent speed is slow.

But did you try another torrent client?

[TheHellSite]

Just tried it with transmission in the same vm using the same port...
Multiple torrent files, large and small ones, download just fine.

[TheHellSite]

I just downloaded 2 torrents with a size of around 6 GB each simultaneously in qBittorrent and Transmission.

Transmission finishes both torrents without an issues and decent speeds.
qBittorrent drops the speed of both torrents again to around 10 KB/s each and doesn't go up again.

It is definitely not an issue with... my operating system installation, my vpn tunnel setup, my vpn provider or my network.
It is clearly an issue with qBittorrent in some way! After restarting qBittorrent, while the torrents are still running, the speed goes back to normal.

[smestarz]

I am not sure if this helps but here are my two cents,.
What I can suggest is Start your computer fresh and then download. It should do it well.
I use Qbittorrent on Windows 10,
When I start computer and Qbittorrent, it downloads at fast speed and completes the torrent, but if i Download another torrent, then it would download for say 300 MB at high speed which it downloads and stores on RAM Cache, but then this cache does not write on the Drive where the torrent is being download, since the cache is full, it does not download at higher speed, the speed will go down till the cache is cleared. I came to this forum because I was searching how to clear Cache without restarting the computer so that I do not have to restart the machine each time to download torrent.
This happens only on the HDD, it writes at good speed on the SSD.

[klunky]

I think i have the same issue, i have like 30 torrents download at 90mb/s for 15 minutes constantly, then drops to 40mb/s for like 2 or 3 minutes and then goes back again to full speed

[smestarz]

I think i have the same issue, i have like 30 torrents download at 90mb/s for 15 minutes constantly, then drops to 40mb/s for like 2 or 3 minutes and then goes back again to full speed

What happens in torrent is that, it caches whatever you download (@ 90 mb/s) and then tries to slowly move this cache to the disk, if your drive is slow (read/write) then the cache will be full after the 2-3 minutes and then the speed of download will almost be equal to the speed of the writing,, then when some part of cache is cleared, the speed will increase again, when the cache is full the speed will drop, it could be one of the following
A) slow drive speed
B) Drive has some issues,
C) Data cable or power cable of the drive has an issue,,
check them one by one.

[ghost]

Closing this as this was reported on a very old version. If you can still reproduce it with latest version please comment to re-open the thread or create a new thread.