This issue started a few days ago.
Firefox 6 started having trouble loading pages, especially pages with large numbers of connections, and once I have several tabs open. The pages will keep trying to load, but data stops getting to the browser.
I can "reset" the browser by closing it and reopening.
It's not a connection issue: Chrome on the same system has no issues.
I have completely removed and reinstalled the browser, and have tried the latest stable beta, and the issues persist.
I use news.google.com regulary, and due to the high number of connections, once I've loaded this page I cannot load any other pages. Also, if I open several tabs simultaneously it'll have the same problem.
UPDATE more details and troubleshooting steps taken so far:
I disabled and removed each plugin in turn and tested the browser: especially with aggregation sites such as news.google.com, pages will either take forever to load, will not load at all, will load once and then not reload, or any combination of the above.
Then I removed Firefox completely using RevoUninstaller and deleted the Mozilla folders in the Appdata directories in the user profiles and the Mozilla and MozillaPlugin trees in the registry. Total uninstall. Then reinstalled with the latest, 7.0.1 or something like that. Same exact issue.
The one other thing I was very loath to do was to do a system restore. However, my system restore apparently only goes back a week or so, and this issue has been going on longer than that. So no dice.
The issue seems most problematic when I try to load multiple pages at once, which I do frequently. If I wait for pages to load before starting the next page it doesn't have as many issues. Pages with lots of different sections like ads or social media integrations or other things that would tend to pull from many different domains tend to have the most problems.
UPDATE system info and further details:
I also have Chrome and IE9 installed on this Windows 7 computer, which is running 8GB RAM and a current Intel CPU. The system is less than a year old, laptop, touchscreen, from HP.
The number of tabs does not seem to have a particular effect, except when those pages each load large numbers of items from different domains. For instance, news sites that load social network items and ad items and in general seem to be the ones loading the most from different domains seem to be the most problematic. So long as I only load one or two at a time it's not an issue. But once I try loading several simultaneously or add a bunch before one completes loading, it'll trigger the problem.
Sometimes the problem is just extremely slow load times. Other times it's completely dead stopped connection with no data moving at all to and from FF. Other browsers are not effected.
about:config
values mentioned by @tom-wijsman below and increased them. I'll report back if this fixes things.