Vista Beta 2 Nvidia driver problem

I recently installed Vista Beta 2, I have been testing Vista with each new
build. Nvidia released new drivers to go along with the Beta 2. When using
those drivers, or the ones that already come w/ Vista the result is stutting
window movement and usage. For example, when I run a screen saver, it seems
to stutter every second. I installed the older drivers that were included
with builds 5365 and previous (87.45 nvidia driver). When I install this the
stuttering is gone. Why are the newer drivers causing my vista to stutter.
It makes it seem like my cpu usage is high even though it is not. I am
wondering if anyone else is experiencing this. My videocard should be more
then able to handle it. 6800gt. My computer is also fairly new. Any
solutions?

I would also like to add that I first had this problem with the last build,
5381, with the drivers that were included with it, being that they were
updated from the 5365 drivers

MSI K8N Neo4 Platinum SLI
AMD 3700+ San Diego
MSI 6800GT 256MB PCI-E
WD 160GB SATA2
Corsair 1GB XMS PC3200
Lite-On DVD-RW
Lite-On CD-RW
OCZ Modstream 520w
Zalman CNPS7000B-Cu LED
Thermaltake Tsunami
Viewsonic 17" LCD