I run several Windows Virtual Machines (VMs) on my Mac with VMware Fusion. Even VMware Fusion has a great performance for Virtual Machines I am really happy about every performance increase I can get. I made a list with some tuning tips.

• First use Windows Classic Theme
• Deactivate System Protection (You also win some Diskspace)
• Under System Properties –> Advanced –> Performance –> Choose Adjust for best Performance
• Deactivate Autostart objects with MSCONFIG

There are a lot of more tips out there but I thinks these are pretty important.