I'm working on an application for Honeycomb and have tried out various themes for it, including the default Holo theme, Holo Light and Holo Wallpaper. My layout is using a HorizontalScrollView with ImageViews and I've found that it gets a bit laggy when using the default Holo and Holo Light themes. It's super fluid with the Holo Wallpaper theme, though, despite it including a bitmap background.
I've even tried making my own theme with a bitmap background, but that just slows down everything even more.
I'd like to have a speedy ScrollView, so if anyone has an answer to why some are faster than others, please let us know :-)
It sounds like you are drawing too many layers. The Holo theme, especially when hardware accelerated, has a default background image on the window. Try to remove it if it's not visible.