Both Win 7 64-bit and XP are very slow after upgrade to Parallels Desktop for Mac v6

I have been a Parallels user since v4. I saw a performance improvement with v5. But when v6 came out. Both Win 7 (64-bit) and XP run significantly slower. I have tried playing with the memory settings, allocating 1 MB and 2 MB's and using adaptive hypervisor with the "faster virtual machine" option, but none of these make any difference. Also, the amount of programs I have open in either Mac OS X Snow Leopard or in the Win VM's make little difference.

I use a MacBook Pro 17" 2.66 GHz Intel Core 2 Duo with 4 GB RAM and a HD with 77.64 GB left on it.

Can anybody help?

 

I submitted a problem report: "Your problem report has been sent to the Parallels Support team with ID 7135533"