How much memory did you allocate to the Virtual Machine? (It's in the VM settings)

>I installed Virtual PC with Windows XP Mode on Windows 7 Pro 64. My experience is not very positive. It feels like a drunk/slow version of XP. For example, when I go to the command prompt and type any letter it takes about 5 seconds for the letter to appear. I installed the Virtual PC in order to possibly continue doing VFP9 support and development on the Win 7 64 PC. But not seem to be practical (at least after initial test). Has anybody had better experience with this?