From Bugzilla Helper: User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.0rc1) Gecko/20020417 BuildID: 2002041711 Certain animated gifs move much more slowly in RC1 than in the monthly build for 0.9.9. Reproducible: Always Steps to Reproduce: 1.Launch the attached animated gif in monthly build 0.9.9. Note the speed at which the penguin moves. 2.Launch the same animated gif in the RC1 build. Note the speed in which the penguin moves. 3. Actual Results: The penguin in the animated gif moves much more slowly in RC1 than in 0.9.9. Expected Results: Animated gifs should move at the same speed in RC1 as in 0.9.9.

FWIW, the testcase animates at the same speed that it does with IE

dunno about 0.9.9, but that's right that build 2002050504 is slower than IE6 for this gif.

This test case animates at about the same speed in RC1 as in IE 5.5. HOWEVER, it animates dramatically faster in Moz 0.9.9 and in NS6.2. Is the decrease in animation speed between 0.9.9 and RC1 a regression, or was it done by intent?

This was intentional, see bug 125137. *** This bug has been marked as a duplicate of 139677 ***