[Question] - Dual Core and licencing

[Nakatomi2010]

My understanding of Windows XP and dual multiple processors is that using something like a dual core processor on XP Home Edition is pointless since Home Edition is not a multi threaded application, while professional edition is, so when getting something dual core, it's generally a good idea to get professional so that you can get the full umph out of it....

So, to use both cores on a dual core chip, DO you NEED XP Professional, or not?

I know XP Home Edition will SEE both cores, or more than one processor, but I don't know if it actually uses both of them.....

Title Edited - Please follow new posting rules from now on.

--Zxian

[cluberti]

So, to use both cores on a dual core chip, DO you NEED XP Professional, or not?

I know XP Home Edition will SEE both cores, or more than one processor, but I don't know if it actually uses both of them.....

http://www.microsoft.com/licensing/highlights/multicore.mspx

"Q. How does this licensing policy affect products such as Microsoft Windows XP Professional?

A. Microsoft Windows XP Professional and Microsoft Windows XP Home are not affected by this policy as they are licensed per installation and not per processor. Windows XP Professional can support up to two processors regardless of the number of cores on the processor. Microsoft Windows XP Home supports one processor."

[Nakatomi2010]

So, this means that XP Home definatly does NOT use both cores of a dual core processor right?

[cluberti]

Regardless of the processor, yes, only one processor core.

[gdogg]

where does it say, it dont use both cores? even if it dont.

games can still use both cores.

no diff , cept the windows core then ...

Edited February 7, 2006 by gdogg

[teqguy]

Well, to be brutally honest, dual core in general on a desktop is currently useless.

Windows doesn't acknowledge or take advantage of them, the library of software that's able to take advantage of SMP is fairly small or limited to professional applications that hardly ever have a niche in the desktop user(aka average Joe) market.

As for the "future proof" mentality... look how far that got all of the people who jumped on the Athlon 64 bandwagon for the security of not being left in the dust by "64bit processing". SSE3 came out a year after x86-64 and many applications have already included support for it, whereas x86-64 is still off to a slow start when it comes to adoption. It's a technology that's been available for over 3 years and has still failed to prove its worth.

This is the same road dual core processors are going to have to take... especially considering they're now waiting on x86-64 to get fully implemented before they'll get a taste of the action.

However, to answer your question, yes, Professional is required for multi-core/multi-processor setups, as noted on this comparison of Home and Pro:

http://www.microsoft.com/windowsxp/pro/how.../choosing2.mspx

"Scalable processor support – up to two-way multi-processor support" is the feature you're looking for.

Edited February 7, 2006 by teqguy

[gdogg]

wierd, my xp home, can run two copies of prime95

dont have any smp software, so cant really test that.

both cores work, and work well at that.

and dual core, goes far beyond, useless, its extremly useful, when multi-tasking.

ex. run a game, and a game server, from one machines, no lags, no FPS hit, etc.

still not sure, if that actually means, dual core, rather dual processor.

or else, quad core wouldn't work in xp pro, and you'd have to goto 2k3.

also same goes for intel HT processors too then, they only work under xp pro? and are completly usesless in xp home?

i just used, CliBench Mk III SMP version

from what I can see, SMP works in XP Home, anyway to prove it dont?

Edited February 7, 2006 by gdogg

[LLXX]

Well, to be brutally honest, dual core in general on a desktop is currently useless.

Windows doesn't acknowledge or take advantage of them, the library of software that's able to take advantage of SMP is fairly small or limited to professional applications that hardly ever have a niche in the desktop user(aka average Joe) market.

As for the "future proof" mentality... look how far that got all of the people who jumped on the Athlon 64 bandwagon for the security of not being left in the dust by "64bit processing". SSE3 came out a year after x86-64 and many applications have already included support for it, whereas x86-64 is still off to a slow start when it comes to adoption. It's a technology that's been available for over 3 years and has still failed to prove its worth.

This is the same road dual core processors are going to have to take... especially considering they're now waiting on x86-64 to get fully implemented before they'll get a taste of the action.

However, to answer your question, yes, Professional is required for multi-core/multi-processor setups, as noted on this comparison of Home and Pro:

http://www.microsoft.com/windowsxp/pro/how.../choosing2.mspx

"Scalable processor support – up to two-way multi-processor support" is the feature you're looking for.

I agree. Better one fast core than two, unless you're running *very* CPU-intensive applications that *also* support more than one processor. Otherwise, most of the time the second core is just idling uselessly.

[Bezalel]

However, to answer your question, yes, Professional is required for multi-core/multi-processor setups, as noted on this comparison of Home and Pro:

http://www.microsoft.com/windowsxp/pro/how.../choosing2.mspx

"Scalable processor support – up to two-way multi-processor support" is the feature you're looking for.

You need Pro for Multi-processor support but even Home will support Multi-core processors.

[Nakatomi2010]

However, to answer your question, yes, Professional is required for multi-core/multi-processor setups, as noted on this comparison of Home and Pro:

http://www.microsoft.com/windowsxp/pro/how.../choosing2.mspx

"Scalable processor support – up to two-way multi-processor support" is the feature you're looking for.

You need Pro for Multi-processor support but even Home will support Multi-core processors.

See, this statement is confusing....

If someone is using XP Home Edition, will both cores EVER be used, or becaus Home Edition is incapable of using both cores, all other programs wont either because Home wont communicate with that other core...?

I want this to be a definitive yes or in with maximum clarity so that I can tell customers the exact reason they need to buy Professiona or Media Center Edition...

[nmX.Memnoch]

I've stated this many times before...

XP Home can use both cores of a single-processor, dual-core system. The key here is "single processor". It's about the licensing, not what the kernel can actually support. XP Home is licensed for up to one physical processor. XP Professional is licensed for up to two physical processors.

As far as XP Home is concerned, dual-core processors translate just like a P4 with hyperthreading...and XP Home can use both threads of a hyperthreaded P4. What you cannot do with XP Home is use a multi-CPU system such as a Dual Xeon setup. The second processor will be completely ignored by the OS.

Regardless of application support the OS can still dictate which core a thread runs on. Take a single CPU system and run multiple tasks on it at the same time. Now take a multi-CPU system and do the same tasks. You'll notice that you can do more at once on a multi-CPU/multi-core system without "feeling" the slowdown.

The operating system itself is SMP/SMT aware. Having SMP/SMT aware applications running on top of it only makes things better. Now that dual-core processors have become a reality more and more applications will be adding SMP/SMT support...even games. Take Quake 4 for instance...there's currently a beta patch out to test SMP/SMT support.

Edited February 7, 2006 by nmX.Memnoch

[Bezalel]

The Home kernal is the same as the Pro kernal and will access both cores. It will not access 2 seperate CPUs due to licensing limitations.

Previous home OSs (9x) do not have the capability to access both cores because SMP fuctionality was never built into the kernal

[gdogg]

I can confirm xp home, uses both cores, when @100% cpu, its using half of each core

if you execute 2 threads, that use 100% cpu, its using 100% of both cpus,

even wmp 10, uses a piece of each core.

actually all programs do.

now the question, I want to ask, if a program in xp pro, uses 100% of the cpu with a single thread, will it use 100% of both cpus? vs 50% of each?

[Gaop]

Seems to me like a few people here are having trouble figuring out the difference in "dual processor" and "dual cores"

First of, Dual processor requires 2 sockets on your mainboard for cpu installation. And this setup will probably not work on win xp home, even if you get it to boot it wil only use 1 processor.

Second, Dual cores is only 1 processor, and since winxp home or pro both supports 1 processor this will work.

It's not windows that controls the dual cores, it's all integrated in the processor. So it's the processor that equals the workload on the cores.

[nmX.Memnoch]

now the question, I want to ask, if a program in xp pro, uses 100% of the cpu with a single thread, will it use 100% of both cpus? vs 50% of each?

It depends on how many threads the program is running. If the program is running one thread that uses "100%" of the CPU, it will use 100% of one core. But if there are multiple threads Windows XP can execute some on one core and some on the other...regardless of whether or not the application is actually SMP/SMT aware. However, it will be more efficient if the application is SMP/SMT aware.