How to enable multiple processors on XP SP 3?

How to enable multiple processors on XP SP 3? I've got a Lenovo n100 laptop that's 3 years old. It dual boots the original Windows XP that came with it and Ubuntu, and I just now noticed that the XP installation, on the Task Manager, only shows 1 CPU.
Asked by: Guest \| Views: 332

Total answers/comments: 2

Comments display order:

bert [Entry]

"Run the msconfig utility, go to the BOOT.INI tab, then click Advanced.

The NUMPROC checkbox should be unchecked to use all processors.
As a test, try to check it and see what does the drop-down list contain.
If it contains only the value 1, then something is really wrong.

NOTE : This answer is from 2009, please treat it with respect for its old age.
Especially : No downvotes, please."

bert [Entry]

"This worked for me (VirtualBox XP Pro)...

1) Go into c:\windows (your install path), search for sp3.cab.
Open this cab file with 7-zip (although explorer may be able to natively open the file, if it can't then download 7-zip from sourceforge).

2) a) Extract halmacpi.dll to c:\windows\system32

b) Extract ntkrnlmp.exe to c:\windows\system32

3) Edit c:\boot.ini

Note: You will need to uncheck the Read-only property so you can save your changes. Set back to Read-only once complete.

Copy the line that looks like this:

multi(0)disk(0)rdisk(0)partition(1)\WINDOWS=""Microsoft Windows XP
Professional"" /fastdetect /NoExecute=OptIn

Make the copied entry look like this:

multi(0)disk(0)rdisk(0)partition(1)\WINDOWS=""Microsoft Windows XP
MultiCore"" /fastdetect /NoExecute=OptIn /kernel=ntkrnlmp.exe
/hal=halmacpi.dll

Now you have a dual-boot option to utilize single or multicore (TaskManager will show two CPU graphs if this was successful). If multicore boots and works properly, then you can delete the single core entry from boot.ini."