what do i believe is the culprit? the fact that google added in the shading of the screen behind the dropdown as it comes down. the ICS dropdown on both AOSP and touchwiz were flawless. on touchwiz, it was a perfect 60fps every single time. you could be doing a million things on the s3, flick down that dropdown, and it would come down in a perfect glorious 60fps every time.
then jellybean came. and the dropdown speed was cut in half. and it looks awful. it makes touchwiz feel even laggier/more bloated than it is.
so i'm wondering if any devs out there know of a way to tweak the notification bar so that dropping it down does NOT darken the screen behind it? just keeps it the same brightness, like ICS did. if so, i believe this will reduce the lagginess of the dropdown bar.
to test this theory yourself, do the following...slightly bring down the notification bar to where the screen is still bright, before the shading kicks in. now quickly move your thumb up and down really fast..notice how well the handle of the bar follows your finger? that's because it's 60fps. it looks smooth, rgiht?
now drop it down towards the bottom when it's almost fully down , and the screen is fully shaded behind it. do the same thing..move it up and down really fast with your thumb..notice how it lags behind your movement and just seems like the FPS is cut well over a half? i believe it's due to the shading. which may also be why when you flick it down quickly, it starts off smooth around the quick notifications and then just drops to a really choppy looking dropdown.