Extjs grid checkbox field select all issue

Extjs, i am facing an issue in gridSelectionModel of checkbox grid. When i tried to select all checkbox using grid.gridSelectionModel().selectAll(). For few records it works, but with records more than 500 it makes page not responding. i tried with suspending the events. But all the above does not work as expected. I am using Extjs 4.2.2 version