How to repair SLOW Firefox after update to 3.5.x

I have been experiencing several slow web page loads within the past few days. It got to a point where it was driving me absolutely insane.

At first, I thought it was a Belkin N150 router that I bought. Mostly because the shop where I bought it at was selling it for a greatly discounted rate (even for the Wan Chai Computer Center in Hong Kong). Connecting directly to my DSL modem seemed fine, but connecting through the wired connection of the router would load certain items on certain web pages very slowly.

Then I found this post stating that I should switch to OpenDNS on both my router and my Mac OS X 10.5.7 Network settings. This seemed like a slight improvement.

Then I thought it was an update from Firefox 3.0.something to 3.5.1 and then a couple of days later to 3.5.2 because I started to realize that sometimes when opening a new tab that I would get a Server Not Found message occasionally and have to click re-load for the page to properly load. I also noticed when waiting for a page to load, I could not scroll down or scroll down on other tabs.

The main symptom was that I would see in the status bar that Firefox would be “waiting for ” Usually the host name that was being waited on was was an ad network server or image server.

Where I noticed most of the problem was loading facebook images in a user’s image gallery.

I think I have fixed the issue by following these instructions

1. Type about:config in the address bar, press Enter.
2. Find network.dns.disableIPv6 in the list.
3. Right-click -> Toggle.
4. Restart your Mozilla application and try again.

So far this seems to have fixed the issue, or at least eliminated the non-loading of facebook gallery photos. Images load very fast suddenly!

I have also seen this post which describes disabling DNS prefetch feature which seems to have been causing alot of people problems.

I’m really not sure now whether setting the my DNS servers to OpenDNS was necessary after all.

One Response to “How to repair SLOW Firefox after update to 3.5.x”

  • David Bailey says:

    I think OpenDNS is great. I use it and suggest to my friends that they use it.

    So even if it didn’t help with this, you should keep it.

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