Firefox: Why is it slow once I have some active downloads?

Question

I am on Firefox 3.5.1 on Windows XP. I notice that Firefox become very sluggish the moment I have some active downloads. As soon as the downloads are over, Firefox is back to being snappy.

Why does this happen? How do I fix this?

Answer 1

Unless this also happens with downloads from slow sites, I'd say there is a good chance your download(s) are saturating your bandwidth, causing page loads to struggle to get through the same channel.

Note: if this is the case, basically the only solution is to use some plugin or separate app for downloads that is capable of limiting the bandwidth used by downloads.

Answer 2

The other two answers by jerryjvl and Axxmasterr seem to be right on the problem.
I am just adding a firefox-3.5 compatible download manager that can be tweaked to control.

The addon is called DownThemAll.
Lookup the features at the author's howto-features page

• It pipelines multiple downloads
• Allows multi-part download -- which you can turn off
• Allows a control on the number of active downloads from the pipeline

Start with Multipart download setup to 1 segment per download and,
number of concurrent downloads setup to 1 too.
Check bandwidth availability from firefox.
From there either increase to multipart and concurrent downloading, or,
Choose to pause the download while you are changing pages,
depending on your response experience.

Answer 3

Try using a download manager separate from the built in version. That is how I stopped FF from getting wrapped around the axle.