Since introduction of dual core processors, gamers noticed that gaming performance suffers while running certain games. [H]ard|Bunker noted this in one of their reviews as the "Benny Hill Effect". This tutorial is intended to consolidate a number of fixes we have come across.

There is a certain amount of stuttering or random speedup/slowdowns while running dual core CPU's in single threaded games. The reason for these problems has to do with power state management in some form or another, as these fixes are designed to address specific power state management issues. 

Fix 1: The AMD Driver and Windows Boot Loader

Allows the system to automatically adjust the CPU speed, voltage and power combination that match the instantaneous user performance need. Download this Setup Installation program (EXE) to automatically update all the files necessary for installation. This package is recommended for users whom desire a graphical user interface for installation. This .EXE driver is a user friendly localized software installation of the driver designed for end-users. This driver supports AMD Athlon™ 64 X2 Dual Core processors on Windows XP SP2, Windows 2003 SP1 x84 and x64 Editions.

Install latest AMD Processor driver found here

This driver will add the /usepmtimer line to your boot.ini file. This will both fix problems in some games like Battle Field 2 and will raise few problems in others like World of  Warcraft. So depending on what games you are playing, you might have to edit your boot.ini to reflect the game you are playing.

To manually edit the boot.ini file in WindowsXP or Windows 2003, follow these steps -

  1. Right Click My Computer
  2. Properties
  3. Advanced Tab
  4. Startup and Recovery -> Settings
  5. To edit the startup options manually, click edit -> Edit 


This should bring boot.ini file to edit using Notepad. The boot.ini should like this - 

  
  [boot loader]
  timeout=30
  default=multi(0)disk(0)rdisk(0 )partition(1)\WINDOWS

  [operating systems]
  multi(0)disk(0)rdisk(0)partiti on(1)\WINDOWS="Microsoft Windows XP
  Professional" /noexecute=optin /fastdetect /bootlogo /usepmtimer

Add the /usepmtimer as noted above and it will do what the driver does for you. If it is already there and you still have problems, you might want to take it out and try again, or try one of the other fixes.

Games Fixed -

  • Far Cry
  • Half-Life 1, Counter Strike, Day of Defeat
  • Need For Speed:Most Wanted
  • Unreal Tournament
  • Lineage 2
  • Serious Sam 2

 Fix 2: The AMD Dual Core Optimizer

AMD Dual-Core Optimizer - The AMD Dual-Core Optimizer can help improve some PC gaming video performance by compensating for those applications that bypass the Windows API for timing by directly using the RDTSC (Read Time Stamp Counter) instruction. Applications that rely on RDTSC do not benefit from the logic in the operating system to properly account for the affect of power management mechanisms on the rate at which a processor core's Time Stamp Counter (TSC) is incremented. The AMD Dual-Core Optimizer helps to correct the resulting video performance effects or other incorrect timing effects that these applications may experience on dual-core processor systems, by periodically adjusting the core time-stamp-counters, so that they are synchronized. 

You can download it here

Games Fixed -

  • Far Cry with 64Bit Patch
  • Morrowind
  • Half-Life 2: Source
  • Battle Field 2

Fix 3: The Microsoft Hotfix

Computers that are equipped with multiple processors that support processor power management features, such as Advanced Configuration and Power Interface (ACPI) processor performance states, require Microsoft Windows XP Service Pack 2 (SP2). Additional updates are available to optimize performance and behavior on computers that are running Windows XP SP2. Without these updates, computers that are equipped with these power management-capable, mobile, dual-core processors may experience decreased performance or unexpected behavior.

Note: This problem also applies to x64-based versions of Microsoft Windows Server 2003. However, this article and its associated private hotfix are not intended to resolve timing problems in games and other applications that run on AMD dual-core computers.
For more information, visit here
You can download it here

Games Fixed -

  • Lineage 2
  • Warcraft 3
  • Call of Duty 1
  • Half-Life 2: Source Engine with HDR enabled

Fix 4: Set the Affinity Manually

Finally, the last and least glorious of the fixes is to manually set the CPU affinity of certain programs. This can be done in several ways.
  1. Alt-Tab out of your game, CTRL-ALT-DEL to the Task Manager, Under the Processes tab, right click the .exe file for your game and go to Set Affinity, Uncheck CPU 1.
     
  2. Use special program to launch games.
    This will allow you to set the CPU affinity before loading the game, which is useful for games that don't respond well to Alt-Tabbing.
  3. Use an affinity masking tool.
    Binding of device interrupts to particular processors on multiprocessor computers is a useful technique to maximize performance, scaling, and partitioning of large computers. Interrupt-Affinity Filter (IntFiltr) is an interrupt-binding tool that permits you to establish affinity for device processors on multiprocessor computers. IntFiltr uses Plug and Play features of Windows 2000 and provides a Graphical User Interface (GUI) to permit interrupt binding. This article describes how to install and use IntFiltr to permit a user to change the Central Processing Unit (CPU) on a single computer.
    For more information, visit here
    Some 3rd party tools with better features -


Games Fixed -

  • Aquamark 3
  • 3dMark 2001
  • KOTOR / KOTOR II with Nvidia Beta 84.12 drivers

Conclusion

One of the above solutions should fix 98% of your gaming problems with dual core CPU's. Any comments or suggestions are welcome. These problems are just for older games. As new games come out they will automatically utilize the full power of a multi-core 64bit processor.