Option Explicit
Sub testComment()
    Dim asheet As Worksheet
    Dim rowNo As Integer, colNo As Integer
    Dim myr As Range, s As String, c As Comment
    Dim i As Integer, j As Integer
    
 'определяем используемую область листа
    Set asheet = ActiveSheet

    rowNo = asheet.UsedRange.Rows.Count
    colNo = asheet.UsedRange.Columns.Count
    
'Application.ScreenUpdating = False
'Application.EnableEvents = False
'Application.Calculation = xlCalculationManual

Debug.Print Now

    'перебираем ячейки
        
    For i = 1 To rowNo '=========================== цикл по строкам листа
    
        'формирование строки данных
        For j = 1 To colNo
            Set myr = asheet.Cells(i, j)
            If Not myr.Comment Is Nothing Then
                myr.ClearComments
            End If
            myr.AddComment
            myr.Comment.Visible = False
            myr.Comment.Text Text:="testComment:" & Str(i) & ":" & Str(j)
        Next j

    Next i              '================================
    
'Application.ScreenUpdating = True
'Application.EnableEvents = True
'Application.Calculation = xlCalculationAutomatic
'с этими скобками выполняется 11 сек, без них 8 сек создание 7110 комментов :(

Debug.Print Now
    
End Sub

Sub testDic()

    Dim dicTest
    Set dicTest = CreateObject("Scripting.Dictionary")

    Dim asheet As Worksheet
    Dim rowNo As Integer, colNo As Integer
    Dim i As Integer, j As Integer, k As Integer
    Dim Key As String
    Dim DataValue As String
    
    'определяем используемую область листа
    With ThisWorkbook
        Set asheet = .Worksheets("Лист1")
    End With
    
    rowNo = asheet.UsedRange.Rows.Count
    colNo = asheet.UsedRange.Columns.Count
    
    Debug.Print Now
        
    'загрузка словаря
    For i = 1 To rowNo
        For j = 1 To colNo
            Key = "test___________________________________________________________________________________________________Comment:" & Str(i) & ":" & Str(j)
            DataValue = asheet.Cells(i, j)
            dicTest.Item(Key) = DataValue
        Next j
    Next i
    
Debug.Print Now
Debug.Print dicTest.Count

    'чтение значений по ключу
    For i = 1 To rowNo
        For j = 1 To colNo
            Key = "test___________________________________________________________________________________________________Comment:" & Str(i) & ":" & Str(j)
            DataValue = dicTest.Item(Key)
        Next j
    Next i

Debug.Print Now

End Sub