What's the difference (advantages/drawbacks) between installing Ubuntu physically on a hard drive and virtually by Vmware?

Question

I've installed a Ubuntu 12.10 virtually with Vmware 9.0 and it works fine with me.

My question: what's the difference (advantages/drawbacks) between installing Ubuntu physically on a hard drive and virtually by Vmware

Especially

1. Effect on running programs and using for programming
2. CPU usage and memory

Answer 1

The basic difference is that VM is sharing your RAM and CPU with your primary OS, but installing physically it can use all your RAM space, so VM is less efficient. I’m not sure about the rest.