Currently with large number of records in the grid when column is resized quickly resize may not actually occur.In this case, the browser's JavaScript engine is not able to fire the appropriate events fast enough, due to the large number of records, which impose a performance hit on the page.
Suggested solution: 
it is possible to improve the column resizing performance if the columns are not resized real-time during dragging, but only after the user drops the resize handle.