Variable performance causality: Lags on PC but not Mac?

Variable performance: Causality of lags on PC but not Mac?

Hello Heroes,

We're having an issue with our new course. The series is on spinal cord injuries and this course is on sexuality.
The course is content heavy with lots of custom flash and video presenters. But the problem at hand is that the course plays well on Macs (all the bullet points fade in on timed animation cues) but not well on PCs. We've tested browsers such as FireFox, Safari, Chrome and Internet Explorer between both platforms... each time it seems the Mac browsers favor performance and the cues come in/out on time.

On the PC, the video presenters play well enough but the bullet points and graphic elements (illustrated icons and photographs) lag. Depending on the length of the slide the lag can become considerable.... in a three minute slide the cued elements lag 30 seconds behind!

I've researched around the forums and have found very relevant info. Such as this 101 article on improving download speeds, where it suggests preloaders and reducing file sizes:
http://www.articulate.com/blog/articulate-101-how-to-improve-download-time-for-your-presenter-course/
This course is currently about 500MB.

Another thread with some pointers I've found suggested another options like setting the load slide SWF to 0, and custom preloaders.
http://www.articulate.com/forums/articulate-presenter/7283-delay-loading-flash-content-slides-lms.html

That's all well and good and these are great starting points. However my hunch is that, based on close observation of the performance issues on PC operating systems (tested in XP and Windows 7) is that there isn't enough "juice" to run the bullet points. The presenter video plays fine, it generally doesn't lag when loaded. But I can almost hear a Model-T sputtering inside the browser as it tries to churn out each bullet point on cue. The course has all (onPrev) animation cues set to a fade of "1 second".

Can we change the settings so that the Powerpoint elements get greater priority? Does AP favor swfs and flvs before the nested Powerpoint elements? This could also be a Mac vs. PC issue. What is the reason that these browsers seem to work both ways? We've been at this project for a while...we've completed five courses already and they've tested reasonably well, this is the first of our new batch of courses, however and the video files are larger.

The same phenomenon occurred while using Parallels on the laptop that we're building the courses on... the native Mac side was fine and the PC side couldn't handle the cues.

Can anyone provide feedback?
Advice on tackling the issue is appreciated. If you can spare the couple of minutes, please check out the live beta presentation:
http://www.sci-u.ca/sexuality/player.html

Click in Section 3.1 to find the slide, "Relationships and Role Changes". Let the slide load, then play it straight through without stopping so that the icons and images paint up as well as the bullet points in cue with the presenter.
Please share you results, I'd like to know how the slide presented itself (did the bullet points match?) as well as what kind of computer you're on (laptop or tower/PC or MAC) and what kind of browser you are running.

Gratitude for any assistance you can offer,
Bling2