Comment 23 for bug 113184

Same issue occurs in SeaMonkey and Fx - not 100% CPU, but easily 50%. Sample flash video:
http://www.cnn.com/video/#/video/crime/2009/05/20/seg.cb.langford.police.beating.cnn?iref=videosearch

$ top |grep 15186
15186 gg2xp 20 0 267m 88m 32m R 48.9 8.8 1:03.07 seamonkey-bin <Flash playing
15186 gg2xp 20 0 267m 88m 32m R 46.8 8.8 1:04.48 seamonkey-bin
15186 gg2xp 20 0 267m 88m 32m R 51.1 8.8 1:06.02 seamonkey-bin
15186 gg2xp 20 0 267m 88m 32m R 56.5 8.8 1:07.73 seamonkey-bin
15186 gg2xp 20 0 267m 88m 32m R 51.8 8.8 1:09.29 seamonkey-bin
15186 gg2xp 20 0 267m 88m 32m R 52.8 8.8 1:10.88 seamonkey-bin
15186 gg2xp 20 0 267m 88m 32m R 41.1 8.8 1:12.12 seamonkey-bin
15186 gg2xp 20 0 267m 88m 32m R 26.2 8.8 1:12.91 seamonkey-bin <Flash paused
15186 gg2xp 20 0 267m 88m 32m R 16.6 8.8 1:13.41 seamonkey-bin
15186 gg2xp 20 0 267m 88m 32m R 13.3 8.8 1:13.81 seamonkey-bin
15186 gg2xp 20 0 267m 88m 32m R 17.6 8.8 1:14.34 seamonkey-bin
15186 gg2xp 20 0 267m 88m 32m R 17.6 8.8 1:14.87 seamonkey-bin
15186 gg2xp 20 0 267m 88m 32m R 21.2 8.8 1:15.51 seamonkey-bin
15186 gg2xp 20 0 234m 85m 31m S 35.2 8.5 1:16.57 seamonkey-bin
15186 gg2xp 20 0 234m 85m 31m S 1.7 8.5 1:16.62 seamonkey-bin <Flash killed
15186 gg2xp 20 0 234m 85m 31m S 3.0 8.5 1:16.71 seamonkey-bin

Build identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1b5pre) Gecko/20090520 SeaMonkey/2.0b1pre

Firefox:
$ top |grep firefox
15602 gg2xp 20 0 313m 78m 29m R 50.5 7.8 0:17.96 firefox <Flash playing
15602 gg2xp 20 0 313m 78m 29m R 41.1 7.8 0:19.20 firefox
15602 gg2xp 20 0 313m 78m 29m R 48.5 7.8 0:20.66 firefox
15602 gg2xp 20 0 313m 78m 29m R 50.5 7.8 0:22.18 firefox
15602 gg2xp 20 0 313m 78m 29m R 53.4 7.8 0:23.79 firefox
15602 gg2xp 20 0 313m 78m 29m R 50.0 7.8 0:25.30 firefox
15602 gg2xp 20 0 313m 78m 29m R 28.2 7.8 0:26.15 firefox
15602 gg2xp 20 0 313m 78m 29m R 18.9 7.8 0:26.72 firefox <Flash paused
15602 gg2xp 20 0 313m 78m 29m R 25.2 7.8 0:27.48 firefox
15602 gg2xp 20 0 313m 78m 29m R 20.9 7.9 0:28.11 firefox
15602 gg2xp 20 0 313m 78m 29m R 19.6 7.9 0:28.70 firefox
15602 gg2xp 20 0 313m 78m 29m R 18.6 7.9 0:29.26 firefox
15602 gg2xp 20 0 313m 78m 29m R 17.6 7.9 0:29.79 firefox
15602 gg2xp 20 0 313m 78m 29m R 18.9 7.9 0:30.36 firefox
15602 gg2xp 20 0 296m 75m 28m S 17.2 7.6 0:30.88 firefox
15602 gg2xp 20 0 296m 75m 28m S 4.3 7.6 0:31.01 firefox <Flash killed
15602 gg2xp 20 0 296m 75m 28m S 5.3 7.6 0:31.17 firefox

Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.10) Gecko/2009042523 Ubuntu/9.04 (jaunty) Firefox/3.0.10

$ apt-cache policy flashplugin-nonfree
flashplugin-nonfree:
  Installed: (none)
  Candidate: 10.0.22.87ubuntu2
  Version table:
     10.0.22.87ubuntu2 0
        500 http://archive.ubuntu.com jaunty/multiverse Packages
$ uname -a
Linux gg2xp 2.6.28-12-generic #43-Ubuntu SMP Fri May 1 19:27:06 UTC 2009 i686 GNU/Linux

nVidia Corporation NV25GL [Quadro4 900 XGL] (rev a3), Flash
10.0.22.87 (Note: same w/compiz effects on or off).