With Windows Vista, Microsoft revamped many features and piled on a lot of functionality that Windows XP didn’t have — among other things improving security. An unfortunate side effect of this, though was that Windows Vista was much bulkier than Windows XP and more battery hungry. As a result, up until October most netbooks used Windows XP.
With Windows 7, more new features were added, but this time a more disciplined approach concerning OS bulk was taken, helped, in part, by a large public testing phase. Windows 7 was trimmed down from Vista both in memory and install size, and many of its critical metrics (boot time, etc.) approached the high bar set by Windows XP.
