Raj,
To the best of my awareness, there's no limit beyond the size of the DBF itself. In VFP, you don't 'load' the contents of a grid - the grid is 'data aware', so all you have to do is set the data source/record source of the grid.
However, I hope you have some type of record selection/searching capability in place, becauase that's an awful lot of data to scroll through!
Kevin