Here is a code I tried to open a workbook and got the data:
Dim WB As Workbook
Dim WBdir As String
Dim Start As Long
Start = Timer
WBdir = "C:... some very large workbook ... .xlsx"
Set WB = Workbooks.Open(WBdir)
Debug.Print " Regular " & Format(Timer - Start, "0.000")
Timer total = Regular 38.066 -> 38 seconds is a long time.