Windows 7 shouldn't require much more memory than earlier versions. The biggest difference is all of the additional services that are run by default in Windows 7 Home Premium and above. Shutting down those services should make huge difference. Netbooks still come with 1 GB of memory and Windows 7 Starter and most of them aren't dual core or 64 bit. Windows 7 Home Premium can be tuned down to run like Windows 7 Starter.