So the question is, What NBI are you using?
I originally had the BIOS A06 and used NBI 0.8.5pre. I thought having BIOS A06 was causing issues... so I downgraded to A04.
I reinstalled the OS (10.6.0) using NBI 0.8.5pre. After reinstalling, I ran NBI 0.8.5pre and let it do its thing. Sound worked afterwards. Great, but if you start up the computer using "-v" you'll notice that it actually doesn't install the video card drivers properly.
So, eventually I made this thread. underwhelmed posted that I use a different NBI, specifically: NBI 0.8.4 RC1. I downloaded it, and installed that to the same USB drive that originally had NBI 0.8.5pre, thus overriding that NBI with an older version.
I then proceeded to reinstall the OS again!
This time, I actually got that "Welcome" intro video upon finishing installation, which I never saw before. Then everything just worked... WAY faster than before. There was really nothing else to it. I believe that I also ran Netbookinstaller, that was within utilities of my fresh OS install.
I really do not understand why less people are having this issue, I've been noticing a few people claiming its slower but they never got any good responses...
Hope that helps!
Definitely make sure that, when in dashboard, when you drop a new widget in, that you get the ripple effect, AND also make sure that the top menubar is translucent!
Good luck!