How many processors does Windows XP support?

[ImaNihilist]

I remember reading somewhere that Windows XP ONLY supports two physical cores. Is that true? Does anyone have a definitive answer? What about XP 64? Does anyone know where I can find this information on the Microsoft website?

What I'm getting at is this: if you had a Dual-CPU Dual-Core Opteron rig, would you be able to run Windows XP Professional? If not, what version of Windows WOULD you be able to run?

[agello24]

from what i have seen. it depends on how the xp os is run. i've seen xp on a 133mhz. and some older 75mhz. but it ran like crap.

[ImaNihilist]

Huh?

[I4one]

XP Pro = 2 (or more ?)
XP Homey = 1

can't find much more than that

here's the possible HAL choices

ACPI Multiprocessor PC = Halmacpi.dll
ACPI Uniprocessor PC = Halaacpi.dll
Advanced Configuration and Power Interface (ACPI) PC = Halacpi.dll
MPS Multiprocessor PC = Halmps.dll
MPS Uniprocessor PC = Halapic.dll
Standard PC = Hal.dll
Compaq SystemPro Multiprocessor or 100% Compatible = Halsp.dll

i recall someone posting quad-core pics here (likely eshbach using Pentium D w/HT or something)

interesting;
http://www.microsoft.com/whdc/system/CEC/ACPI-MP.mspx

For example, if the platform has four processors with the ID 0-3, and NMI is connected LINTIN1 for processors 2 and 3, two entries would be needed in the MAPIC table.

[...]

Configuring an MP System to Run ACPI

Earlier sections of this article describe the sections of the ACPI Specification relevant to MP machines. This material should provide the background needed to implement the appropriate ASL and tables for an MP machine to run ACPI. The following section discusses some of the issues crucial to running ACPI successfully on an MP machine.

The first, and most important, step is to understand the hardware details of the machine in question. As stated earlier, the details of the interrupt routing on the machine must be clearly understood. Once you have this information, ask the following questions to ensure an MP machine is correctly running ACPI:

[ImaNihilist]

XP Pro = 2
XP Homey = 1

can't find much more than that

here's the possible HAL choices

ACPI Multiprocessor PC = Halmacpi.dll
ACPI Uniprocessor PC = Halaacpi.dll
Advanced Configuration and Power Interface (ACPI) PC = Halacpi.dll
MPS Multiprocessor PC = Halmps.dll
MPS Uniprocessor PC = Halapic.dll
Standard PC = Hal.dll
Compaq SystemPro Multiprocessor or 100% Compatible = Halsp.dll

i recall someone posting quad-core pics here (likely eshbach using Pentium D w/HT or something)

Hmmm. As I understand it, it's two PHYSICAL cores only, so a PD with HT wouldn't count. I wonder though. Is it even possible to run any version of XP on dual-core dual-cpu rigs?

[Fenixco]

from what i have seen. it depends on how the xp os is run. i've seen xp on a 133mhz. and some older 75mhz. but it ran like crap.

I want some of what he is doing.

[I4one]

see this thread;
http://forums.amd.com/index.php?showtopic=60391
posts 2 and 7 has some info

[ImaNihilist]

see this thread;
http://forums.amd.com/index.php?showtopic=60391
posts 2 and 7 has some info

Hmm. Perhaps it does work. Thanks!

[snickers0129]

I remember reading somewhere that Windows XP ONLY supports two physical cores. Is that true? Does anyone have a definitive answer? What about XP 64? Does anyone know where I can find this information on the Microsoft website?

What I'm getting at is this: if you had a Dual-CPU Dual-Core Opteron rig, would you be able to run Windows XP Professional? If not, what version of Windows WOULD you be able to run?

This will work fine. I just setup a box with dual, dual-core xeon processors and no problems with windows XP (32).

Hyper threading is enabled too, so windows task manager shows 8 processors each with their own usage chart. That's two physical processors, each with 2 cores, each core hyperthreaded for a total of 8 logical processors!

[nails]

windows does not count a dual core as two seperate processors, so you can run a dual core on xp home and you can run a dual cpu rig on xp pro just fine. i think if you need 4 seperate processors, you have to move on to server.

[ksuohio]

Microsoft counts each physical CPU and not cores or virtual cores.

[ImaNihilist]

This thread came back from the grave. Zombie! Die! DIE!

[agello24]

in a maximum pc mag. xp supported two dual opterons. it's that four processors?

[muisejt]

as has been said before in this thread, XP supports 2 physical CPU's, and by physical CPU I mean the square thing you put in the socket on the motherboard

also I'm closing this, please don't grave dig