IceWeasel scrolling lag or download stalling

.
I backed into this problem.
I started a thread about pipelining which noone else was interested in.
In the process I think I discovered both a problem and demonstrated
how to approach it.

From what little I've read, it would appear to be Firefox/IceWeasel specific.

I became aware of IceWeasel 9 browser loading becoming erratic when I first
started playing with pipelining. I was surprised to discover the problem
was there with pipelining disabled. I might be zipping from site to site with
nice responsiveness and then on some site or on some page, things would
'choke' for a few seconds and then resume. I could check my cpu monitor on
lxpanel whenever the stall occurred and see the cpu activity at a maximum for
the duration of the stall.

This effect can be provoked some by surfing to a site with a large page
full of graphics, perhaps some ads and maybe some javascript,
and immediately attempting to scroll past the initially displayed material.

I first tried earlier IceWeasels and found the problem just as acute. Then
I tried IceWeasel 10, experimental, and this problem subsided a lot. The only
difference between the old IceWeasel installs and the new one was that at
first, there was no Ad Blocker for IceWeasel 10.

From what I read, others have discovered this same effect and determined
that the root cause is probably due to overloading the mozilla javascript
machinery with a lot of add-ons. In my case I usually have several ad-blockers
and SQLite Manager. It could be that pipelining doesn't help the situation,
but the problem is there even without pipelining.

Here's an independent view on the matter:
http://www.ehow.com/how_6033196_fix-...refox-3_5.html

I'm now back to fiddling with pipelining and SQLite parameters to see if
I can find a happy set of values to continue with while avoiding the stalls.