This issue has been tracked yesterday with mars.
As a video is better than words, you can have a look at: http://people.canonical.com/~didrocks/slowLP-1.ogv
So here, you can see that:
- only firefox is affected, not chromium
- only LP pages make the rendering slow (3-4s)
- even opening the firefox option dialog over a LP page in Firefox is slow to refresh.
I can add that:
- there is a CPU pick when drawing a LP page.
- I don't have accelerated driver currently enabled, that's what in my mind, show the issue.
- moving another window above a LP rendered page has the same effect of slowness to refresh (chugging)
- I have a 32 bit system
- I'm not the only one to have that. I just think it's obvious on my machine due to the lack of accelerated driver
- I tried with a new firefox profile, same issue
- using safe-mode and removing all plugins has the same effect.
I get the same delay on https://code.launchpad.net/ page (not as bad as in the screencast, but still)
So we tried various things with mars (desactivating JS didn't get everything). A local copied file shows the same behavior.
Deactivating images fix the issue. Unfortunately, we tried a webpage with only images (http://people.canonical.com/~mars/lp-images-test.html) and the issue isn't reproduceable.
If I deactivate CSS, no issue as well.
-> So, it's images + Layout which make this strange bug in FF lucid.
We got until the fact that:
- this page has the bug: http://people.canonical.com/~mars/lp-images-test/0/357235.html
- this one, with some stripped part hasn't it: http://people.canonical.com/~mars/lp-images-test/1/357235.html
leaving it as new and assigning to Maris until we know what's causing it