I think V9 is better optimised for the latest CPUs. I doubt you'd get much speed difference between running it under Win XP or Win 7.
I agree with Jay, if your going to upgrade the OS go for Win 7. I doubt Vista was quite as bad as a lot claimed it was but there's no reason to not go to Win 7.
I cannot offer much more. I assume as you're still using V6 you've not jumped to HD as yet. I'm not too certain about how Vegas, CPUs and RAM stacks up render speed wise with SD. The again render speed has never concerned me that much.

Bob.

"Avoid Vista like the plague!"

Wow. Even the plague avoided Vista? Now that's really telling. ;)

Actually it didn't avoid it, it just wouldn't run on it, even after the patch.

I made the same switch some time back and saw a huge performance increase. Something is wrong. Check to see if Vegas is using all cores when rendering.

You should see a significant performance increase, but I do not know how multi-threaded Vegas 6 was. I don't remember when that came into play, but I remember I had a hyper-threading P4 at the time. I had to set the option for the correct number of threads at that time to get any real improvement. Try adjusting the thread count in the Option Preferences section.

You didn't mention what speed the CPU is. If it is not running multi-threaded and the CPU is not clocked faster then your P4, then you would not see much improvement.

Sorry, Vegas 6 was a while ago and my memory isn't like it used to be. Even if it is 12gb in size.

KK

kk, where the hell did you get a 12gb memory? was it an upgrade? who's your maker?

i came with the factory default of 640mb and find i have to keep swapping out memory(ies).....