This object was bound to A Devexpress Grid. The time it takes to show query result on this grid is 1:40 (mm:ss)

The same object was bound to DataGridView. The result is nearly 3 (seconds)

I wonder why do I encounter with there is big difference ? Everyone test this condition easily.

An example from my app: 1 Million row table containing production of individual pieces. I've just opened our transaction maintenance form and randomly selected a date range in 2006. The grids (DevExpress) filled in about 15 seconds with 20,000 rows. Each transaction row populates two different grids (within a tab control) and one of the grids has extensive DexExpress subtotals. Each grid contains about 20 columns. I opened the form in the Visual Studio IDE.

I think your issues are more in finding and presenting the required dataset to the BO you are using in the DevExpress grid.

Cheers, Peter