What is "background download"?

I recently installed the game again, and now in the fps bubble I get a "background download" message; it runs for a while and eventually stops. What is it downloading?

Could it be because my fps is so low? I can't get anything better than 7 or 8 now, even on lowest settings. It's not my connection; I think maybe my graphics card is dying.

The game was designed to only download minimal amount to play while rest is downloaded in the background or when needed. You can force the game to download everything by creating a shortcut to gw.exe with -image switch. Something like:

"C:\Program Files (x86)\Guild Wars\Gw.exe" -image

This could take hours. It exists immediately when done so if happened to add -image to your original shortcut, remove the switch again to be able to play.

Ok, thanks. I was just curious since I hadn't seen it until recently.