I don't have the code right now, but is somethin like this:

form_load event
daList.Fill(MyDataSet, "MyTable")

MyCombo.ValueMember = "ID"
MyCombo.DisplayMember = "Name"

MyCombo.DataSource = MyDataSet.Tables("MyTable") 'This line slow down
'If i comment the line, it loads fast.
'--------

My DataSource has 5 rows