Flash Content on Safari Stutters Badly...

Question

I am trying to troubleshoot for my sister who has an iMac G4 800mhz; 768mb RAM; 64mb VRAM; running 10.4.10
Quicktime trailers play fine for her in Safari, (or on her desktop), but with Flash content, like at Youtube, or Comedy Central, the video playback stutters badly. I define stutter, as unwatchable jumpy video, and audio that plays back better than the video, but also drops out occasionally.
I've upgraded her to the the latest version of Flash, and that did nothing. I also downloaded Firefox, just to check another browser, and Flash content stutters there to.
My next idea, as a test, was to download a flash file to her desktop, and see if it stutters there without using Safari, and it's flash plugin, as the player.
So I downloaded a flash file from youtube, (by doubleclicking it in the activity window, which automatically downloads a file called, "get video," with no file extension, and a generic icon.)
I then added a .flv on the end of the file name, and the icon turned into a flash icon.
Now, I want to note, on my computers, when I add a .flv on the end of the name of one of these files I've downloaded from Youtube, when I highlight it in a finder window under column view, I see a preview of the movie, which I can play there. I can also ctrl click, and choose, open with other, (because flash player will not open an flv file), and choose Quicktime as the app, it opens and plays.
On her computer, when I highlight the same file in column view in her finder window, there is no preview visible, just a large flash icon, and the file will not open with her Quicktime app either.
Now, I could care less whether she can play the darn things on her desktop, though I am perplexed that I cannot. (I was just troubleshooting.) Btw, we are both using the same versions of OSX 10.4.10; Safari 2.0.4; Quicktime 7.2; and Flashplayer 9.0
All I want is for her to be able to play Flash content on Safari without the stutter.
Any suggestions?

Answer 1

Thanks for your reply.
I've been hearing nothing but crickets!
I guess it's just the old machine that's the problem. Thanks for the confirmation, -that you have had the same experience.
No wonder the "five bar," pros that work these boards have had no solutions to offer. They're usually, on the money.
I am aware of downloading the flv files and converting them with iSquint. I've told her she can do that, and while that would be fine for me, (though I don't have this problem), it's not a solution she is happy with. I use my activity window to find and download flash files all the time, that don't have a download link readily available. I suppose if she wants the vid badly enough, she will call me and I'll walk her through it.
She has been talking about upgrading her system, for some time now, so this will just be one more reason for her to do so.
Thanks again!