It seems like BlackBerry is getting multiple reports of slow performance and high CPU usage on the latest versions of BBM for BlackBerry. We heard from a few users that there was some battery drain issues with 10.3 but now BlackBerry has confirmed that they are investigating an issue on their Knowledge base. For now BlackBerry is saying to go into the system monitor on BlackBerry 10 and check if BBM is using an unusual amount of CPU over the last 12 hours. If it is they are asking that you report it to them following their instructions.
Check out the details here: