求助！IIS5.1的WebService放到IIS7.5下执行缓慢

VB.NET+ACCESS
WebService代码如下：
    <WebMethod()> _
    Public Function Upload(ByVal strSqls() As String) As Integer '传入参数为需要执行的SQL语句的字符串数组，一条Update语句一条Insert语句。
        Dim dbConnection As OleDbConnection = getAccessConnection()
        Dim dbCommand As New OleDbCommand
        dbCommand.Connection = dbConnection
        Dim trans As OleDbTransaction = transBegin(dbConnection)
        Dim intSqlIndex As Integer = 0
        Dim intResult As Integer = 0
        Try
            '循环执行执行SQL语句，先执行Update，执行Update返回1行以下时再执行Insert语句。
            For i As Integer = 0 To strSqls.Length / 2 - 1
                dbCommand.CommandText = strSqls(intSqlIndex)
                dbCommand.Transaction = trans
                intResult = dbCommand.ExecuteNonQuery()
                intSqlIndex = intSqlIndex + 1
                If intResult < 1 Then
                    dbCommand.CommandText = strSqls(intSqlIndex)
                    intResult = dbCommand.ExecuteNonQuery
                    intSqlIndex = intSqlIndex + 1
                    If intResult < 1 Then
                        trans.Rollback()
                        dbConnection.Close()
                        dbCommand.Dispose()
                        trans.Dispose()
                        dbConnection.Dispose()
                        Return -1
                    End If
                End If
                intSqlIndex = intSqlIndex + 1
            Next
        Catch ex As Exception
            trans.Rollback()
            File.AppendAllText("C:\inetpub\wwwroot\ExteriorEstimateWs" + "\Log.txt", DateTime.Now + " : exception message : " + ex.Message + " ; exception stacktrace : " + ex.StackTrace + " ; sql : " + strSqls(intSqlIndex) + "      " + strSqls(intSqlIndex) + "       " + Chr(13) + Chr(10))
            dbConnection.Close()
            dbCommand.Dispose()
            trans.Dispose()
            dbConnection.Dispose()
            Return -1
        End Try
        trans.Commit()
        dbConnection.Close()
        dbCommand.Dispose()
        trans.Dispose()
        dbConnection.Dispose()
        Return 1
    End Function
在自己机器WIN XP上的IIS5.1上运行速度可以，一秒能执行60条左右。但是把这个WebService放到WIN SERVER 2008的IIS7.5上之后运行速度慢的要死。一秒平均10条以内，查了也没有解决，求大神帮忙。。。

补充：.NET技术 ,  Web Services