Experts Round Table

WinXP and dual-core problems

WinXP and dual-core problems:

from the June 2006 issue of MaximumPC < www.maximumpc.com >

While this is not a common problem, it is well documented that sometimes WinXP, apps, or games, have a problem with the dual-core cpus.

The biggest problems are:
apps/games running super-slow, super-fast, crashing, stuttering, hanging, or a combination of these.

The two main causes are:
1) the cpus (cores) get out of sync.
2) trouble with the 'slowdown/speedup' power saving "feature" of the cpu.

Out of Sync

While most problems reported are with AMD X2's and FX's, this is due to their popularity with gamers. Intel's dual-core's have also been reported as having problems.

Try adding "/usepmtimer" (without the quotes) to the end of the BOOT.INI file. This will make the cores stay sync'ed all the time.

Or you can go to www.amd.com/us-en/assets/content_type/utilities/amdcpu.exe for their "dual-core processor driver" update, which does this for you.

Intel does not seem to have one out yet, so you need edit the BOOT.INI manually, to apply it to theirs.

Throttle down/up

If you run a cpu intensive benchmark several times, and the scores are all over the place, it might be that XP is not bringing the cpus back up to full speed after they have throttled down.

MicroSoft has a "hot fix" for XP, but to get it, you have to contact them, and ASK for the hot fix for issue 896256

But why bother. Go to AMDzone.com and search for "hot fix" (without the quotes), and download it from there.
After you install the patch, you need to create a registry key, to enable it.

Open REGEDIT, go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager.
Make a new key, and name it Throttle.
Right click the new key, select NEW, then DWORD Value. Type in: PerEnablePackageIdle for the value name.
Right click PerEnablePackageIdle, click Modify, and type a "1" (no quotes) in the value field, and make sure Hexadecimal is selected.
Click OK, exit out of Regedit, and reboot to enable the patch.

Still no joy?

If it seems to be just one or two games or apps, that's giving you grief, try limiting it/them to just one cpu (core). Officially known as setting the CPU Affinity.

To do this:
Start the app or game.
Press Alt-Tab to go to the Desktop.
Press Cont-Alt-Del and select Task Manager.
Click the Processes tab, locate the app or game, Right click it, scroll down and click set affinity.
Uncheck one of the cpu boxes (all but one, if quad-core is out when you read this).
Click OK, and close Task Manager.
Press Alt-Tab to go back to the app or game. It should now be running on a single core.

As a last resort, you can disable one of the cores.
Click START > RUN > type MSCONFIG
Click the BOOT.INI tab, and then the ADVANCE OPTION button.
Check the /NUMPROC box, and set it to 1.
Click OK, exit out, reboot.
To see if there is only one core running, Right click the TASK BAR, click TASK MANAGER, go to the Preformance tab, and under CPU Usage History, you should see just one cpu graph, not two.

NS,NR!!