Comment 2 for bug 383435

Similar symptoms here, w/Firefox 3.0.11 & 3.0.12 installed/updated via apt on Ubuntu 9.04 (netbook-remix).

I've noticed that my hard drive is constantly active during the delay. @Keepiru, do you see this as well, or do you just see heavy CPU activity?

"I keep saying scrolling here because it's the most obvious case, but I'm pretty sure all browser operations freeze during the lag time."

Definitely all browser operations cease, or at least all UI ceases. If my mouse cursor is in a non-standard state when the delay starts, it stays that way. Clicks and keyboard operations are ineffective. I *think* mouse and keyboard actions usually queue up and then are all executed when the delay ends.

I see the delay after initial page-loads have completed (almost every time), as well as when scrolling. Unlike the OP, I generally see this behavior immediately after starting Firefox and then throughout the life of the process. I'm not sure that it gets worse over time. So my problem could be different.

Mine Happens on everything from rich AJAX-y pages with multiple external dependencies, to HTML-only pages without any external dependencies. @Keepiru, do you notice any kinds of pages where it doesn't happen, or do you see it across the board?

I suspected Xmarks but not so much now that I've seen a similar report from someone else. Will disable Xmarks all the same and report back.