IMPORTANT For users with Dual Core or Pentium 4 with HT (Hyper Threading Technology)

Is your OEM notebook or desktop correctly configured in Windows XP to support Dual Cores (regardless if its Intel or AMD based)
Last Updated: 03-27-2007

It is confirmed that Sager (as well as many other OEMs) DOES NOT configure this hotfix for their Dual Core notebooks.
Note: The pictures are only examples, there are not always supposed to be identical... only similar. And they are more "similar" when the CPU Usage is greater (ex. video encoding, playing games, watching movies, etc...).
My pictures is using a multi-threaded program (meaning that it fully supports and utilizes both cores). Most programs that a typical person uses are probably not multi-threaded, but the performance should still be improved. Both graphs are NOT always identical






The performance of your multitasking and games (ex. BF2, Oblivion, etc) would be a lil F'ed Up if the dual cores are not both being utilized because the setting for your Windows isnt set correctly. This hotfix is for those that want the most out of their Dual Cores. If you are just a casual PC user, this hotfix might not do anything for you. But if you multitask and game, you definitely see an increase in performance. As well as if you do Professional Audio editing and Video editing, this will also help you greatly.

Therefore (here's how to check -OR- do it yourself)
Required:
- Windows XP (Home, Pro, MCE) with Service Pack 2 (even when using Apple Bootcamp, NOT Virtual PC)
- Any system (desktop or notebook... even Apple's MacBook's) with multi-cores, multi-processors, multi-logical processors (Hyper-Threading)
---- Intel: Pentium 4 w/ HT, Pentium D, Core Duo, Core 2 Duo, Dual Core Xeons
---- AMD: Athlon 64 X2, Turion X2, Dual Core Opterons

1) (for Intel CPUs) Check to see if the mandatory Windows XP Hotfix Patch: KB896256 (NOT automatically downloaded with Windows Update) is installed.
if not download KB896256 XP patch and install it.

1) (for AMD CPUs) Check to see if the mandatory Windows XP Hotfix Patch: KB896256 (NOT automatically downloaded with Windows Update) and the AMD CPU drivers are installed.
if not download KB896256 XP patch, AMD CPU Driver and install them. (for AMD Dual Core Optimizer info read Note 2)
Note 1: Only install the AMD Driver if you have an AMD CPU.
Note 2: The AMD Dual-Core Optimizer was AMD's answer to Microsoft's Multi-Core fix... originally, to get the hotfix, one would have to email Microsoft to get it... screw that. Therefore, AMD released their Optimizer to give the public (with AMD CPUs) a way to utilize both cores. If you install the AMD Optimizer and it works without problems, then you would NOT have to install the the WinXP hotfix.
BSOD's (Blue Screens of Death).... If you own a Clevo D900K (A.K.A. Sager 9750, Alienware Aurora m7700, etc) notebook, DO NOT install the AMD Dual Core Optimizer... incompatible. So if you experience BSODs (on any computer) from the AMD Optimizer, then go into Safe Mode and uninstall it. You will still have optimized dual core as long as you do the rest of the guide.

The registry location: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager should have a key named Throttle there, if not make it by right clicking, point at New > Key... name it Throttle.

3) (Still in registry) Inside Throttle key: should be a DWORD called PerfEnablePackageIdle with the value of 1. If not there, right click, point to New > DWORD... name it PerfEnablePackageIdle.
*** Note: You should type 1 in the Value data box to enable the performance state policy behavior ( increases performance)



4) Quit Registry.

5) Now look at your boot.ini to make sure that the command /usepmtimer is there, by right clicking on My Computer go to Properties, click on the ADVANCE tab, then under Startup and Recovery click on Settings, then click on EDIT....make sure your boot.ini has the /usepmtimer in there (located in the last line), if NOT then just copy and paste /usepmtimer in there. (NOT the entire boot.ini example)

Note: If you have an AMD dual core and installed the AMD drivers, the /usepmtimer would be inserted into your boot.ini for you.

BOOT.INI example

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=optin /fastdetect /usepmtimer



Go to File and then Save (to save the changes to your BOOT.ini).

Restart your computer.
That's it!

NOTE: The BOOT.ini that I have given was meant for an example only. I would not recommend you to copy all of it and overwrite your own, unless if you are specifically using XP Pro SP2 on the first partition of the harddrive. Everyone else (XP Home, MCE2005, OEM pre-installed it onto different partition, etc.) should just add the /usepmtimer only.

FYI: The /usepmtimer in the BOOT.ini is a "switch" that forces the system to use a steady clock in place of the CPU frequency... for certain timing functions. Thats as basic as you can explain it.

Just to point out that this info has been floating around in other forums and discussions from as early as Nov 2005.  That inquirer article is based on a thread started in June 2006..they picked up on it a tad late.    

 

If your system is running fine then you may just want to leave it alone and resist the urge to tinker.  Now if you're getting stuttering on dual core systems then read up on it.  It doesn't appear to help core2 systems btw.   So, just be aware.