[dddie]

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;

namespace RunUO
{
	public class LoadMul
	{
		public static List<short> m_ItemIDs;

		const string sStatic = "statics0.mul";
		public static void Main()
		{
			if( !File.Exists( sStatic ) )
			{
				Console.WriteLine( "File not exist!" );
				Console.ReadKey();
				return;
			}

			System.Threading.Thread.CurrentThread.Priority = System.Threading.ThreadPriority.AboveNormal;

			Console.WriteLine( "\t\t\tTime (ms)" );
			Console.Write( "Original function\t" );
			Test( LoadMul_0 );

			Console.Write( "Remove Seek\t\t" );
			Test( LoadMul_1 );

			Console.Write( "Remove Contains\t\t" );
			Test( LoadMul_2 );

			Console.Write( "Use BufferedStream\t" );
			Test( LoadMul_3 );

			Console.Write( "Remove BinaryReader\t" );
			Test( LoadMul_4 );

			Console.Write( "Move buffer allocation\t" );
			Test( LoadMul_5 );

			Console.ReadKey();
		}

		public delegate void Callback();

		public static void Test( Callback callback )
		{
			System.Threading.Thread.Sleep( 25 );
			m_ItemIDs = new List<short>();
			Stopwatch time = new Stopwatch();
			time.Start();
			callback();
			time.Stop();
			m_ItemIDs = null;
			Console.WriteLine( "{0}", time.ElapsedMilliseconds );
		}

		public static void LoadMul_0()
		{
			using( Stream pStatic = new FileStream( sStatic, FileMode.Open ) )
			{
				BinaryReader reader = new BinaryReader( pStatic );
				long length = pStatic.Length / 7;
				for( int i = 0; i < length; i++ )
				{
					short id = reader.ReadInt16();
					if( !m_ItemIDs.Contains( id ) )
						m_ItemIDs.Add( id );

					pStatic.Seek( 5, SeekOrigin.Current );
				}
			}
		}

		public static void LoadMul_1()
		{
			using( Stream pStatic = new FileStream( sStatic, FileMode.Open ) )
			{
				BinaryReader reader = new BinaryReader( pStatic );
				long length = pStatic.Length / 7;
				for( int i = 0; i < length; i++ )
				{
					short id = reader.ReadInt16();
					if( !m_ItemIDs.Contains( id ) )
						m_ItemIDs.Add( id );

					reader.ReadBytes( 5 );
				}
			}
		}

		public static void LoadMul_2()
		{
			using( Stream pStatic = new FileStream( sStatic, FileMode.Open ) )
			{
				BinaryReader reader = new BinaryReader( pStatic );
				long length = pStatic.Length / 7;
				bool[] buff = new bool[0x4000];
				for( int i = 0; i < length; i++ )
				{
					short id = reader.ReadInt16();
					buff[id] = true;

					reader.ReadBytes( 5 );
				}
				for( short i = 0; i < buff.Length; i++ )
					if( buff[i] )
						m_ItemIDs.Add( i );
			}
		}

		public static void LoadMul_3()
		{
			using( Stream pStatic = new BufferedStream( new FileStream( sStatic, FileMode.Open ), 64 * 1024 ) )
			{
				BinaryReader reader = new BinaryReader( pStatic );
				long length = pStatic.Length / 7;
				bool[] buff = new bool[0x4000];
				for( int i = 0; i < length; i++ )
				{
					short id = reader.ReadInt16();
					buff[id] = true;

					reader.ReadBytes( 5 );
				}
				for( short id = 0; id < buff.Length; id++ )
					if( buff[id] )
						m_ItemIDs.Add( id );
			}
		}

		public static void LoadMul_4()
		{
			using( Stream pStatic = new BufferedStream( new FileStream( sStatic, FileMode.Open ), 64 * 1024 ) )
			{
				long length = pStatic.Length / 7;
				bool[] buff = new bool[0x4000];
				for( int i = 0; i < length; i++ )
				{
					byte[] buffer = new byte[7];
					pStatic.Read( buffer, 0, 7 );
					int id = (buffer[1] << 8) + buffer[0];
					buff[id] = true;
				}
				for( int id = 0; id < buff.Length; id++ )
					if( buff[id] )
						m_ItemIDs.Add( (short)id );
			}
		}

		public static void LoadMul_5()
		{
			using( Stream pStatic = new BufferedStream( new FileStream( sStatic, FileMode.Open ), 64 * 1024 ) )
			{
				long length = pStatic.Length / 7;
				bool[] buff = new bool[0x4000];
				byte[] buffer = new byte[7];
				for( int i = 0; i < length; i++ )
				{
					pStatic.Read( buffer, 0, 7 );
					int id = (buffer[1] << 8) + buffer[0];
					buff[id] = true;
				}
				for( int id = 0; id < buff.Length; id++ )
					if( buff[id] )
						m_ItemIDs.Add( (short)id );
			}
		}
	}
}

Intel Pentium 4 - Nortwood 3 GHz, RAM 3 GB PC3200
HD 300 GB MaxLine III 7200 rpm, SATA, 16 MB cache

Hyperthreading: Enabled

                        Time (ms)
Original function       26866
Remove Seek             11357
Remove Contains         529
Use BufferedStream      475
Remove BinaryReader     281
Move buffer allocation  205

Hyperthreading: Disabled

                        Time (ms)
Original function       26289
Remove Seek             11240
Remove Contains         523
Use BufferedStream      484
Remove BinaryReader     293
Move buffer allocation  189