MacBook slows down when playing movies

[deskjet]

About a month ago my Macbook (which I bought 4 in May) started getting really slow when I played movies with quicktime or used Front Row. The entire computer slows down and the fan ramps up for about 2-3 minutes until the movie starts playing. After that everything is normal again until I start playing a movie or go back to the Front Row menus. This seemed to start when they updated the latest version of QT but that may be a coincidence.

Any ideas what could be causing this?

thx.

[deskjet]

Oh, when I check the activity monitor it shows that CPU goes to 100 and Quicktime is unresponsive. RAM is fine.

[Cromulent]

What codec are the movies in? Are they HD?

[deskjet]

Not sure which codec, they're mostly .avi files but it seems to happen anytime QT or Front Row is used regardless of the file type.

[Hawkeye411]

Not sure which codec, they're mostly .avi files but it seems to happen anytime QT or Front Row is used regardless of the file type.

Have you Repaired the Permissions on your HD?

Cheers. :apple::)

[deskjet]

Yes, I've repaired the permissions. Doesn't seem to have made a difference.

[deskjet]

Another thing, the movies play fine with VLC. Only Quicktime and Front Row cause the slow downs.