Desktop background "automatic picture change" issue.

[xoggyux]

Hi guys,
I've been having this problem, I have mac configured such that it changes the background picture every 5mins (since i get bored of the same all the time) the pictures are all JPEG in the 350-450KB most of them and resolutions of 1600x1200, the thing is that when I'm watching a video or even a flash animation and the background changes, the computer kinds of lags (more like it keep a frame for extra time, and then skip a few others, the sound doesn't stop) for a few milliseconds (not enough to call it a freeze, but certainly annoying.)
What could it be? How could I fix it?

 

[Repo]

Refreshing a wallpaper can actually use a large amount of computer resources for just a few seconds, enough to notice a lag, especially if you're watching video.

What are the specs of your laptop?

 

[Consultant]

Your harddrive might be set to sleep when possible. The slight delay probably due to time to spin up the HD.