Actually, my experience of the latest WIP (with cover art images rather than videos) is that scrolling was worse than 0.9n6 ;-( This was because in 0.9n6 the system seemed to load the images into memory, so that once you had scrolled down the list once, it was quicker scrolling up and down (until you rebooted).
In the latest WIP, it seemed to load the image from disc every time you went up and down the menu, even if it had already loaded the image before, so it seems it no longer keeps the images in memory. This made scrolling up and down slower than 0.9n6.
I've reduced the problem a bit by reducing the size of the images, but the WIP still seems a little less responsive than 0.9n6, which is a shame. I'm hoping there is a configurable option in the WIP to optionally make it behave the same as 0.9n6 in this manner, but I haven't heard back from BJ (I posted this in the thread of WIP problems).
I realise that you're talking about videos rather than images, which I wouldn't expect to be kept in memory anyway, so I'm probably describing a different issue than you are. I just thought it worth me repeating my above observations in a thread specifically about WIP scrolling. <