uGUI ScrollRect too slow?

Hi,
I have a list made with a ScrollRect and about 30 items inside, each of which is a Panel with a couple of images and texts, all done using the new Unity UI system.
However scrolling is incredibly slow, especially on mobile devices, when profiling that’s where the issue seems to be:

Canvas.SendWillrenderCanvases

which takes up to 8ms per frame.
So am I doing something wrong? Or is that just a limit of the current UI system? I’m using Unity 4.6 RC3

Thanks in advance!

Old question but I bumped into this and felt the need to answer.

Most likely your canvas is set to Pixel Perfect. Disable this and your performance could quadruple (that’s what happened to me)