If your BlackBerry Smartphone is running slowly, take the following steps to get it to work at its best speed;
Close Unused Applications
Press and hold the key with the BlackBerry Icon to see all running applications, and close unnecessary ones.
Clear the Event Log
The BlackBerry Event log is a list of all events and errors that has ever happened in the device. To see the event log, From the Homescreen hold alt and press lglg and the below screen comes up.
Press the Menu key and click on “Clear Log”
Click on Delete, and all the event log would be deleted.