Swf - stream or full download?

I have sort of a general Flash question.

Are swf’s supposed to start playing back only once the entire file has been downloaded to the client machine, or start “streaming playback” just as soon as the client has downloaded enough data to start playing at all.

Let’s say I have a 20mb file. Here’s what I’ve noticed: Firefox 3 starts playing back the file right away, only having downloaded a small percentage of the file - essentially offering “streaming” playback. Internet explorer 7, on the other hand, seems to wait for the entire swf to be downloaded before it starts.

Is this a known issue? This is a problem for me because it’s about a 30 second wait for anyone trying to view the files on IE, while on Firefox, they start up within a few seconds. I tried putting in a preloader, but that slows things down considerably on Firefox, because now instead of streaming, even the Firefox users have to wait for the entire file to download before they can begin viewing it.

To see what I’m talking about for yourself, click this link in both IE and Firefox and see the difference.

I would love to get this worked out. Thanks a ton in advance for any insight! :cowboy:

** EDIT: I’ve seen other sites where they got the streaming effect in both IE and Firefox… I’m wondering if that means they must have Flash Media Server or they are doing something simple that I’m overlooking **