AngleSharp ClosedXML Dapper DocumentFormat.OpenXml Newtonsoft.Json System.Data.SqlClient Dapper Newtonsoft.Json System.Data.SqlClient System.Net.Http System.Threading.Tasks ClosedXML.Excel void Main() { Stopwatch sw = new Stopwatch(); sw.Start(); Console.WriteLine("start memory usage: " +System.Diagnostics.Process.GetCurrentProcess().WorkingSet64 / (1024 * 1024) + $"MB"); var path = @"D:\git\MiniExcel\samples\xlsx\Test1,000,000x10\Test1,000,000x10.xlsx"; using (var workbook = new XLWorkbook(path)) { Console.WriteLine("A1 : " + workbook.Worksheets.First().Cell(1,1).Value); Console.WriteLine("end memory usage: " +System.Diagnostics.Process.GetCurrentProcess().WorkingSet64 / (1024 * 1024) + $"MB & run time : {sw.ElapsedMilliseconds}ms"); } }