HP/Compaq :: Better NVidia Drivers

I've got a HP Pavilion dv6000z notebook. It came pre-installed with Windows Vista Home Premium 32-bit but, I recently changed the OS to Windows XP Home Edition SP3 32-bit. It was a completely new installation of the OS.

Now, I've got a weird problem. I watch the NBA games on this website for international viewers at ilp.nba.com and it goes through an external company named RayV. They provide their own software to watch the games on, I believe it is a p2p kind-a program [if that helps?]; RayV Viewer. In this, the broadcasted video size is 608x336 or something like that and averages about 800k-1000k speed/bandwidth?. They call it the "HD" version.

The problem is, the video continuously "stutters" every 4-7 seconds.

My room mate has the newer dv5t series notebook with an intel core 2 duo 2.0ghz processor nd an intel integrated graphics adapter [x3100/4500?] nd the video works absolutely perfectly on his notebook. Same goes for my friends Apple Macbook [old "lower spec'd" white version] however with mine it has this continuous stuttering problem. I've tried increasing the process priority through task manager but that didn't help either.
Most HD videos work fine in WMP [.mkv 720p] though they stutter every now nd then too.

Like about every 10 - 13 minutes, maybe a little bigger gap but it happens nonetheless.

I've tried the 182.08 drivers from laptopvideo2go.com & the DOX 182.46 version as well as the 86.38 version from windows update but none of them have been able to solve it. Any ideas as to what I could try?

I'm currently downloading the beta of Windows 7 to see how that works on this notebook, I believe the RC is just about to be released & is on some sites so could give that a shot but would love to solve it in XP itself.