Swapping CPUs - how well do OS's adapt?

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venm11

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I need to swap CPUs around on installed OS's - mainly windows 7 and linux. The question is, if you're changing the CPU to a very different one (eg, athlon 1x <-> phenom x4) how will the OS react? Will it automatically adjust the kernel to SMP and load whatever drivers it needs?

The reason is that my low-power server will occasionally need a *lot* more more processing power for various projects, and it's simple enough to swap the CPU from my gaming machine.
 
It shouldn't be an issue, at least with Windows. I would check MSCONFIG afterwords though to make sure it's not limiting the CPU to 1 core though.
 
Not a problem with any recent Linux installation. Windows may want to re-activate itself; YMMV.
 
Anything that creates a fingerprint of your system will be broken. The biggest effect is going to be DRM restricted content, such as movies and music. It may also impact any programs that you have "activated" on your computer.
 
Demon10000 said:
Anything that creates a fingerprint of your system will be broken. The biggest effect is going to be DRM restricted content, such as movies and music. It may also impact any programs that you have "activated" on your computer.
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I was under the impression that it was mostly dependant on the MAC address which is usually tied to the motherboard. That way upgrades should not affect any activiation for the most part.
 
Windows activation is 100% tied to the motherboard and no other component.
cyclone3d said:
I was under the impression that it was mostly dependant on the MAC address which is usually tied to the motherboard. That way upgrades should not affect any activiation for the most part.
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You can add another NIC to your computer thus giving the system 2 mac addresses. The onboard is simply that, a NIC that is manufactured as part of the board. MAC addresses of nics have nothing to do with Windows activation.
 
cyclone3d said:
I was under the impression that it was mostly dependant on the MAC address which is usually tied to the motherboard. That way upgrades should not affect any activiation for the most part.
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If it's a factory installed OS from the likes of Delll, HP, etc, activation is tied to a key embedded in the motherboard's BIOS. You can change everything in the system and not trip reactivation as long as the BIOS key remains present.

Otherwise activation is tied to a list of hardware component's IDs (network controller, hard drive, CPU, etc). and is designed so that changing one device in the list shouldn't trip a reactivation.
 
bigdogchris said:
Windows activation is 100% tied to the motherboard and no other component.You can add another NIC to your computer thus giving the system 2 mac addresses. The onboard is simply that, a NIC that is manufactured as part of the board. MAC addresses of nics have nothing to do with Windows activation.
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umm... yes they do. It's three of the 10 things Windows checks when verifying the hardware hasn't changed.
 
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Windows prompted me for re-activation when I gave a win2k3 VM 2 extra cores. So it won't break anything but will most definitely want you to reactivate.
 
Biznatch said:
Windows prompted me for re-activation when I gave a win2k3 VM 2 extra cores. So it won't break anything but will most definitely want you to reactivate.
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I wouldn't say it would most definitely trigger a reactivation. It's more likely that nothing at all will happen.
 
FWIW, the motherboard on my wife's PC died, beautifully swollen MB caps. It was an E-machine T5254, which was running an AMD Athlon 64 X2 BE-2350 @ 2.1 GHz. I did a wholesale swap of motherboard, processor and memory to the AMD box in my sig. The only thing I had to do was reactivate windows, nothing else at all. Problem is, it still looks like an E-machine T5254! It's a wolf in sheep's clothing, as far as a mom box goes. No 'mom box' cracks, thanks
 
Windows doesn't always do an auto switch on the HAL when going from a single-core/single-thread CPU to a multi-core/multi-thread CPU, and can cause a BSOD on boot.
 
Forgot one thing, "Hat Monster" from Ars made a great post back in the W2K/XP days, search their CPU forum for "Swapping your board without so much as a reinstall". I think Windows 7 does automatically a lot of what he did with manually (kudos to MS). It's still a great read for you youngins
 
j-sta said:
Windows doesn't always do an auto switch on the HAL when going from a single-core/single-thread CPU to a multi-core/multi-thread CPU, and can cause a BSOD on boot.
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Which windows (version) ? In theory, it ought to detect it as it is enumerating and identifying all the devices. It should at least detect the change. Whether the kernel dependency is ... 'evaluated' ... I guess is what we're talking about. I think it used to be that it required a reinstall of windows, because only one kernel (and those were particular to the exact processor config) was dropped in at compile time.

I was very, very mildly pleased when XP noticed up an HT processor and saved me the trouble of reinstalling. Presumably later OSs are smarter, and there are enough concrete reports above to make me think it is so. Unless it is not.
 
venm11 said:
Which windows (version) ? In theory, it ought to detect it as it is enumerating and identifying all the devices. It should at least detect the change. Whether the kernel dependency is ... 'evaluated' ... I guess is what we're talking about. I think it used to be that it required a reinstall of windows, because only one kernel (and those were particular to the exact processor config) was dropped in at compile time.

I was very, very mildly pleased when XP noticed up an HT processor and saved me the trouble of reinstalling. Presumably later OSs are smarter, and there are enough concrete reports above to make me think it is so. Unless it is not.
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I've had it happen in XP.
it's certainly possible it could happen in 7, although I haven't seen it myself.
 
cyclone3d said:
I was under the impression that it was mostly dependant on the MAC address which is usually tied to the motherboard. That way upgrades should not affect any activiation for the most part.
Click to expand...

In regards to DRM, CPU is on the top of the list and the mac of the NIC is way, way down there...
 
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