Since 2002 when Microsoft introduced Windows XP, its signature operating system has proved to have more stamina than anybody would have originally thought. Despite missteps in Vista, that OS still managed to introduce useful new features, and set the stage for Windows 7.

This chart provides a rundown of some of the major features introduced in each Windows iteration, as well as a quick look at the minimum hardware requirements for XP, Vista, and 7. Keep in mind that Windows 7 is still in its testing phase, though it's not expected that other major features will debut before it's released during the coming holiday season. You can download the Windows 7 release candidate from CNET

Comparing Windows: XP vs. Vista vs. 7
Windows XP Windows Vista Windows 7
Minimum hardware
  • Processor: 300MHz
  • RAM: 128MB
  • Super VGA graphics device
  • HD: 4.2 GB (for SP3)
  • Processor: 1GHz
  • RAM: 1 GB (32-bit), 2 GB (64-bit)
  • Support for DirectX 9 graphics device with 128MB of memory
  • HD: 20 GB (32-bit), 40 GB (64-bit)
  • Processor: 1 GHz
  • RAM: 1 GB (32-bit), 2 GB (64-bit)
  • Support for DirectX 9 graphics device with 128MB of memory
  • HD: 16 GB (32-bit), 20 GB (64-bit)
  • Luna theme
  • Introduces task-based windows options
  • Skinning possible but difficult
  • Desktop Cleanup Wizard automates removing old icons
  • Aero theme
  • Introduces transparent panes, window animations, live thumbnails of running programs
  • New desktop sidebar supports gadgets
  • Supports touch screens
  • Aero theme
  • Supports slideshow backgrounds, RSS and theme packs
  • Introduces Aero Shake and Aero Snap
  • Desktop gadgets can be placed anywhere
  • Supports multitouch on touchscreens
  • Replaces tree navigation by default with task pane
  • Improves image handling
  • Offers thumbnail previews and group views
  • Supports some metadata
  • Task pane integrated into toolbar
  • New breadcrumb navigation
  • New metadata display
  • Improved icon resolution
  • Some documents can be edited from the preview pane
  • Support for federated searches and libraries
  • Virtual folders aggregate content from local and networked drives
Start menu
  • New layout
  • Devices and some Control Panel options appear in menu
  • Added search box
  • All Programs folder changed to a nested format
  • Configurable power button
  • User profile picture
  • Taskbar jumps appear in the Start menu and replace the right column when viewed
  • Documents, Pictures, Music buttons now link to their libraries
  • Control Panel options have been integrated into search results
  • New look
  • Hideable icons in System Tray
  • Refreshed look
  • ALT-Tab hot key now shows preview thumbnail of program
  • Interactive mouse-over preview panes
  • Replacement of the Quick Launch bar with pinned programs
  • Program-specific jump lists based on pinned programs
  • Aero Peek for mouse-over desktop viewing
  • Revamped System Tray
  • Introduces Universal Plug-n-Play
  • New driver library allows for downgrading drivers when necessary
  • Debuts portable device API, designed to communicate with cell phones, PDAs, and portable media players
  • Introduces Sync Center for managing data synchronizations
  • New Device Stage provides a centralized, unified window for managing all aspects of printers and portable devices
  • Introduces context-menu CD and DVD burning from Windows Explorer
  • Supports multiple versions of a single DLL to prevent programs from overwriting each other
  • Introduces Hibernate and Sleep modes
  • Remote Desktop for accessing a computer from another location
  • Fast user account switching
  • Built-in drive partitioning
  • More powerful screen-capturing tool
  • Hybrid Sleep and better configuration options for more nuanced power management
  • User-based file-type associations
  • Previous Version automatically backs up changes to individual files
  • Expands Windows Explorer disc burning to include ISOs
  • Introduces XP Mode
  • Expanded options for disabling components
  • Can search text in scanned TIFF
  • Additional power-saving features for laptops

As others have noted, Windows 7 does one thing similar to Windows XP: It doesn't require a major hardware upgrade. In fact, it can run on less powerful machines than Vista. By making 7 as accessible as possible for existing computers, Microsoft looks to be angling to regain lost market share and confidence by giving users a operating system they don't have to struggle with. Until Windows 7 makes its public debut, though, this is little more than informed speculation.