If it doesn't say anything then it's triple buffered. (unless you override in the config file.)
How is the off-screen background blue only in 2.5... Maybe I can add another option "bg_color" for this and have it default to 0 (black).
[edit] @franpa : Does it look the same in 2.5 if you set the resx, resy to 640x480 and let your graphics card do all the work?
