1. DSi has 2 graphic cards for 2 screens.
2. It also has 2 CPU. First is 66 Mhz and is used for physics. Second is 33 Mhz and is used for touch screen.
3. DS and DS Lite also has browsers, but they need Memory Expansion Pack inserted in slot 2. DSi has 16 MB of RAM (comparing to 8 + 4 in previous), so it is much faster.
4. Excepting screen resolution, DSi is strong enough to use Windows 98 on it. The problem is that it would need 2 CPU working together so there would be no touch screen.
5. DS and DS Lite has menu similar to Wii. DSi's menu one column of icons that can be adjusted so you can put your favorite aplications on its beginning.