Oscillation on high throttle

I just built this little quad in the 250+ size. If is slightly overpowered and hovers at less than 40% throttle. Though it behaves better with less weight than with more. This behavior is present at all times but gets worse with more weight. In the video I have a 3000mA battery mounted on top and what happens is that the quad when given lot of throttle starts oscillating, going to one side or even flip upside down. I was wondering if this is because of any sync problem or just PID’s. Any idea?
[youtube]ifvH9njZxFU[/youtube]

@philsson,
Your video link is broken. How about providing either tlogs and/or data flash logs to help troubleshoot your issue.
Regards,
TCIII GM

[quote=“TCIII”]@philsson,
Your video link is broken. How about providing either tlogs and/or data flash logs to help troubleshoot your issue.
Regards,
TCIII GM[/quote]
I did not manage to embed the link properly. Here is the video of the problem.
youtube.com/watch?v=ifvH9njZxFU
I am running a clone of the APM without Data flash. I have bluetooth though but the connection is unstable, maybe I can get some logs from the Droid Planner.