Acpi Multiprocessor Pc Ethernet Controller Driver

This can usually be seen in the task manager, where performance shows only a single graph, although one diagram per CPU is selected.

I talk about cores here, the same applies to multiple processors.

Those are usually used on servers, though, where few people would start fixing the HAL.

Hardware Abstraction Layer HAL The reason is usually, that the normal ACPI HAL (Hardware Abstraction Layer) has been installed which does not support more than one core.

When a windows XP system is installed with only one core active, and more core(s) isare added later on, the CPU id does not change no redetection is done, the other cores are not recognised.

Another reason may be that the ACPI PC is not the same as ACPI UP, and only ACPI UP is able to support, and thus detect, more than one CPU.

In the case of VirtualBox, the situation may also be caused on the IO-APIC not being enabled on install.

According to SUN, XP Uniprocessor with IO-APIC is slower than without.

You can downgrade it, though, which is not a good idea there is no way back.

Using devcon.exe: Forced HAL Upgrade I found a very interesting post about the devcon.exe, a tool provided by MS as the command line version of the device manager, and its application to the HAL switch problem.

After running devcon, you reboot the system; after the reboot, XP re-detects all hardware, and the requests another reboot.

This may change some of the hardware names, especially the LAN connection may get the number 2.

Hidden Devices You can use the show-hidden trick of the device manager to display the old devices and remove them: set devmgrshownonpresentdevices1.

Doing it manually Before I found the post by hedrums above, I tried to do it manually.

They are loaded so early and completely in the boot process that they are no longer needed (used) in a running system, and can just be replaced.Yet, I never managed to copy and rename the files correctly.

Acpi Multiprocessor Pc Ethernet Controller Driver