Setting Global Rate Limits Upload Speed also throttles download speeds.

[mr-september]

qBittorrent & operating system versions

Tested with 4.5.5 and 4.6.4 x64
Windows 11

What is the problem?

Settings > Options > Speed > Global Rate Limits > Upload:

Limiting Upload speeds also heavily throttles download speeds.

I tested a few Upload Rate limits:

• 1 KiB/s drops download speed by about 95%
• 5 KiB/s by about 80%
• 10 KiB/s by about 20%
• 20 KiB/s by about 10%
• 40 KiB/s and above to unlimited gets normal download speeds.

For reference, at uncapped Upload Rate my upload fluctuates around 20-80 KiB/s.

Additional context

This is particularly problematic and counter-intuitive because throttling upload is one of the first things to try when troubleshooting unusually low download speeds. Whether there was a systematic error or just by bad luck for some time, this step ensures that there is systematic error going forward.

For comparison, this is not a problem in utorrent. Upload speeds and slots could even be limited down to 0 wherever possible, and downloads continue at full speed.

[LazyPajen]

I think you apply rate-limit also for the "transport" overhead, my guesstimate is 10-15% of the speed/data is for transport
Untick the 2second last row. yes there will be traffic - but that is for the transport overhead

Try It!

[mr-september]

Hi, thanks for the suggestion.

I just checked and the transport overhead is already unticked. I tested on factory default settings by deleting qbittorrent.ini, then changing only the Global Rate Upload Limit, and nothing else.

[Griss168]

Internet communication is always two-way. Because you always send some peer a request for what data you want and he sends you a response with that data. That is, if you reduce the number of sent requests, then naturally you have to get back less data.

And if someone limits the upload below 20kB/s, then we can honestly say that it goes against the very idea of Torrent.