179662 - Mozilla "stutters" while scrolling down on a page with many images

Status: RESOLVED DUPLICATE of bug 163975

(Core Graveyard :: Image: Painting, defect)

Description

[Frank Klein]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.3a) Gecko/20021111
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.3a) Gecko/20021111

I was reading the page mentioned above, and I hit the "scroll down" marker at
the bottom of the scroll bar to scroll down.  Once the entire document was about
half to 2/3 done, the images that were loading or finished loading scrolled very
slowly, stuttering noticeably.  You have to wait for the document to be mostly
or fully loaded before it happens.  

I tried it in 1.0.1 and also in K-Meleon 0.7, and both exhibited the same
behavior.  MSIE 6 did it flawlessly... that, and the faster scrolling it does
when you click the "scroll down" button (which has nothing to do with browser
speed), gives it the impression of being very fast with this page, while Mozilla
feels quite slow and choppy.  

While this stuttering is happening, CPU utilization goes to 100%.  

Computer is a 900 MHz mobile Duron, 320mb RAM, XP SP1, modem connected at 31200 bps.

Reproducible: Always

Steps to Reproduce:
1.  Load the URL above, and let it finish downloading the whole document, with
all images, before scrolling it at all.
2.  Hit the "scroll down" button at the bottom of the scroll bar and hold it down.

Actual Results:  
The scrolling of the first image stuttered-- was choppy and very slow.

Expected Results:  
Scrolled smoothly and not stuttered.

Comment 1

[Frederic Bezies]

No stuttering at all. WFM using one hour old CVS based build, WinXP-Sp1.

I also have a DSL line. Maybe stuttering is caused by your connection ?!

Comment 2

[Frank Klein]

It happens even when the image is finished loading, so I do not think it was my
connection.  Perhaps your computer is faster than mine?  CPU utilization goes to
100% and it stutters; maybe yours is powerful enough to not need 100% cpu time.  

Comment 3

[Oliver Klee]

The scrolling is a bit irregular for me, but it doesn't seem to be slower than
on other sites.

Tested on 2002110808 Win2k, GeForce 2 GTS, Athlon 1400.

Comment 4

[Frank Klein]

I am sorry; I did not mean to imply that there was anything unusual about this
site.  This is the one I was using when I noticed the stuttering, but I am sure
it happens on many other sites as well-- I just did not take much notice of that
before.  

Comment 5

[R.K.Aa.]

The images at the page are all scaled. Mostly scaled down, a few scaled up. So
most of the images there are really bigger than they appear on pate.
Resolving as duplicate of bug 163975

*** This bug has been marked as a duplicate of 163975 ***