Extreme browser lag triggered by simultaneous downloads


Description of the issue: Brave Browser slows down significantly after parallel download of multiple files over a longer time
How can this issue be reproduced?

  1. Go to any cloud service or local server and download 6 or more files at the same time (the files should be on the bigger side so it would take around 20min+ each, when you would individually download them).

  2. Leave the downloads running for some time and use the PC as normal

Expected result: After some time or immediatly after starting all the downloads Brave Browser starts slowing down significantly. When you then pause i.e. 4 of the 6 downloads you notice Brave running smoother. When you then resume the 4 paused downloads it lags again.

Brave Version( check About Brave): v 1.92.141

Additional Information: I must add that I encountered this issue on multiple machines (2 Desktops & 1 Laptop) and in multiple prior Brave versions without manually resolving it. I also need to add that this is the first time I am having this issue again after 2 months or so.

Yesterday I did download 6+ files at the same time which should take around 2h for all to finish. After 20-40min my browser slowed down so much that I can’t even scroll through a website without 3 seconds of delay between every scroll.

I also feel like that once I triggered this issue, every singular download slows my browser down by x-amount. Even on the next day and after restarting my PC and Brave.

I have also cleared my cache of the last 4 weeks with no success.

Other tasks on my PC work perfectly normal while my “lagging” Brave Browser is open and I only notice the issue when I use Brave or the browser in general.

To me it sounds expected behavior rather than an [Brave] issue. You’re basically saying “when I download several massive files at the same time, browser performance decreases”. Having multiple active downloads will cause an uptick in memory consumption, cpu processing and write operations. The same thing would happen if you were to open several larger applications all at the same time.

If you download the same amount and kind of files using a different browser (Chrome, Edge, Opera, etc) I suspect you’d see the same or similar performance dip. If you test this and that’s not the case, let me know.

I have this problem with even only one 7 GB file. My CPU or memory is not even close to being used fully. Cpu is around 10 percent and i have 32Gb ram so its not a issue either. This is clearly and issue with the browser. I also have decent rig with Ryzen 5 5600x.

Also this issue happens on both windows 11 and linux (cachyos). So that narrows it more.

I have this exact problem on debian linux Im only downloading 2 or 3 1-2GB files and im lagging for some reason My CPU or memory is not even close to being used fully as well