This is really weird and I have no idea what could be causing this.
I have this simple Flash site:
The main interface is loaded, and then it starts to preload a few external JPG images.
The problem is that with IE it is taking about FOUR times (or even more) the time to load the same pictures with FF!
In a slow connection such as a 128K the main interface takes the same time to load either on FF aswel IE - about 5-10 seconds. Then, it starts loading the external pictures - in FF it will take about 20 seconds more and in IE it will take about 80 seconds more!
It is clear to me that the problem is not in the site loading itself, but in the contents loading. I can’t see what in the browser could be interfering in the SWF, unless that the IE Flash plugin have some known (or unknown!) bug regarding to MovieClipLoader!
The only thing I can have in mind, is that I am not terminating the listeners in the onLoadComplete events, so theoretically they would be keeping the CPU busy even after the pictures finish to load (I spawn about 30 listeners, one for each picture). However, I doubt that this is the reason or else it would make FF slow down too, indeed?
Also I noticed that when running the application in the authoring environment (control+ENTER) but loading contents from remote server, it have the same behavior as when loaded within IE (slow loading).