Hello ched78
If you believe there is something wrong with your new MacBook, contact the retailer who sold it to you for a professional check.
Otherwise, unless you get better suggestions here, consider the following suggestions:
(0) Search
Photo Booth > Help > Photo Booth Help on your Mac for "Using video backdrops" (without the quotation marks.) Instructions on how to properly use the video backdrop with your new MacBook are shown there.
After you have made your video as instructed there, check the quality again to see if it is better.
(1) If your video does not look better than your earlier Photo Booth movies, quit Photo Booth.
Then open your
Home / Pictures / Photo Booth folder.
Open your movie file using QuickTime Player, and play the movie to to check its quality in QT.
(2) If the video quality is unacceptable to you when played with either QuickTime or Photo Booth, try all the suggestions that you have not yet tried that were offered to "RNobleman" in his thread at
http://discussions.apple.com/thread.jspa?threadID=1289170.
If, after trying everything that has been suggested in that thread, you still find an unacceptable and equivalent lag in both Photo Booth and WebcamTweaker videos played back in QT Player, it seems that, like RNobleman, your quality demands are higher than Photo Booth's backdrops can deliver.
(3) If you cannot accept lower quality video that with the Photo Booth "backdrop" you want, the only workaround I can suggest is to use different software. Once you find iMovie or some other video software that gives video quality you find acceptable, you can decide whether you need to pursue more professional painted or projected backdrops with that software.
EZ
Jim
PowerBook 1.67 GHz w/Mac OS X (10.4.11) G5 DP 1.8 w/Mac OS X (10.5.1) External iSight