Is virtualization in Windows less battery intensive than Wubi? Than a disk install?

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http://askubuntu.com – I read that running Ubuntu through a virtual machine such as VMware Player or VirtualBox is actually less costly on a laptop's battery than Wubi because it utilizes Windows' drivers, which are optimized for Windows by the hardware manufacturers, as opposed to the Linux drivers, which are less optimized and thus more costly for your system. Is this true for Wubi? If so, is it also true for a "normal" Live CD/USB installation? (HowTos)