choppy video when upgraded to alpha 3

[rikardo1979]

Did you use update to Alpha 3 or fresh install ?

If you updated, maybe you can try to do the fresh install of Alpha 3 ?

There should never be a problem to play 720p video under any circumstances as the RPi is more than capable to handle this files so it makes me think that you have something somewhere what is bugging.
If you have all as should in HW part and use the Alpha 3 (or even the earlier versions back to 0.6.x) it should play 720p or even 1080p smoothly.

Please do a backup before you do your fresh install on SD card ( use XBMC Backup Add-on from official XBMC Repo) or try it on spare SD Card if you have some