[notauser]

Performance is much improved on Linux these days (at least the x64 version).

My Macbook Pro running Ubuntu 9.10 uses about 5-10% CPU at most for flash video, and usually a little less for flash-only sites. The only problem is that when it crashes the browser is sans-flash until you restart it.

[jrockway]

Of course, playing the same flv file full-screen in mplayer uses almost no CPU at all.