I've never used more than one desktop, even though there are more there by
default. Three questions:

-- Are the applications on each desktop "live" still operating full speed?

-- Doesn't this slow the computer down?

-- Is there an easy way to have different wallpapers on each desktop in
Ubuntu? I've tried "Wallpapoz" but couldn't get it to provide a unique
appearance for each desktop. I just want to know where I am and different
wallpaper is the only way I can think of.