The ram itself is twice as fast per cycle, assuming it has the same Mhz. SDRAM means Single Data rate wheras DDR means Double Data Rate. That means it transmits info twice per cycle rather than just once. However, if you have a SDRAM chip at 400Mhz and a DDR chip at 280Mhz, the DDR chip is only about 40% faster. The clock cycles on these would be great, but I doubt those are released info.
Of course, even at the same cycle count, it will be nowhere near a linear jump in overall performance. Will be a nice one just the same.
No. They launched the app, and it was running from then on. Here's an example of a similiar situation, one many people might be familiar with. I might run the web browser. Change apps, check gmail, and go back to the browser. Same things pop up in browser as before, it never closed. Is the browser always running? No. Is the browser running since I launched it? Yes. They launched the app on first running it, and it stayed running since. You can even see them do it in some videos. Not sure why people have a hard time with that. They launch the app like any other docking app, it just doesn't close on undocking.
Edit: Here's
one video. Look at ~1:19. When he selects webtop, you can see it loading, the app was not running previous to this point. Skip ahead to 6:55 or so. Note as he puts the atrix in the dock, the app is already running because he just started it and takes a fraction of the time to launch because it's already in memory. There is no reason you cannot close this app, and there is no reason for it to be running if you don't launch it.