Windows Vista SLOW Using Parallels 6

I used to have Windows XP on Parallels 4 and everything ran fast. XP had some error that kept making it crash so I upgraded to Parallels 6 and then I upgraded to Vista and now Parallels runs so slow I can hardly use it. Everything is slow both in Parallels and on my Mac right for the start up of Parallels. Any ideas how I can get it to speed up. Here's what's going on in Activity Monitor:

prl_vm_app 15 CPU, 406MB of Real Memory, 3.93 GB of Virtual Memory
Parallels Desktop 5 CPU, 42MB of Real Memory, 1.22 GB of Virtual Memory

I'm on a MacBook Pro running Mac OSX.

 

My Windows 7 has never been faster since I switched to an iMac with Parallels 6 (unlike my PC the Mac has an SSD and that helps).

 

Thanks for that info. I'm first going to try upgrading to Parallels 7 and if that doesn't change anything I'm moving up to Windows 7. I know Vista has some performance issues.