flash player lags when not the active screen

I have come across a problem I was wondering if anyone else was experiencing.

I have come to notice that when Storyline is published as flash and contains a video screen capture, that it will run smoothly while that screen is the active screen (mouse is on the training screen) but will lag if you so much as move the mouse off the training screen and hover over the desktop or another window. Moving it back makes it run smoothly again.

At first I thought it was a RAM issue with opening/loading things while the training is running, but it occurs just by moving off the screen.

this is an ussue for me as when my training contains a video tutorial I place a timer in the master slide that changes a 'count' variable when the user has viewed the tutorial for long enough, this in turn enables the person doing the training to do the assessment. This way I know they are not jumping ahead.

I've found that when flash player lags, as described above, the timer loses time. Over a 2 and a half minute video it was out 40 seconds.

Does anyone know if this is a flash player issue, does it get less resources if you're not actively on the screen with the flash playing?

Thanks