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I have a Virtualbox VM running Windows 7. When I open Start -> Right click "Computer" -> Properties, I get the real CPU name and plausible CPU speed (not sure if it's exactly the same).

Now I want Virtualbox to change the CPU name to something different, say an old Core 2 Duo running at a lower speed. How would I do that?

nyanpasu64
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    Related [question](http://superuser.com/q/625648/2357) for Windows XP guest. – Cristian Ciupitu Jun 28 '14 at 21:47
  • That one's not answered. I'd wait and see if this does any better. – nyanpasu64 Jun 28 '14 at 22:28
  • I've just answered it. Does [my answer](http://superuser.com/a/774596/2357) work for you, too? – Cristian Ciupitu Jun 28 '14 at 23:13
  • It says "Intel(R) Core(TM)2 CPU (big space) 6600 @2.40 GHz (space) 3.36 GHz" which is not very convincing. I think the 2.40 GHz is part of the CPU model information, while the 3.36 GHz is the reported current CPU speed. How do I change the reported clock speed? – nyanpasu64 Jun 29 '14 at 00:08
  • I don't think that's possible. And after all, most modern CPUs have variable speed thanks to their power management features and overclocking. If you want to limit the speed, I suggest editing your question accordingly mentioning that you've already figured out the model name part. By the way, there's already a similar question on this topic: ["Limiting CPU speed in a virtual machine"](http://superuser.com/q/265322/2357). – Cristian Ciupitu Jun 29 '14 at 00:13
  • When I underclock my real CPU to 2.2 GHz turbo boost (not standard multiplier) and reboot the virtual machine, it remains on 3.36 GHz (not even my real CPU speed) Additionally, changing the execution cap does not change the reported CPU speed. – nyanpasu64 Jun 29 '14 at 00:18
  • It looks like the way Windows 7 figures out the frequency is a bit broken. See [Windows 7 doesn't recognize my overclock](http://www.tomshardware.co.uk/forum/255132-29-windows-doesn-recognize-overclock) on Tom's Hardware forum. – Cristian Ciupitu Jun 29 '14 at 00:23
  • I underclocked my main PC to 2.4 GHz plus turbo boost, and the VM still says 3.36 GHz. How does Windows get it? CPUID? Related instructions for getting clock? Hardcoded algorithms for probing chipset? (unlikely, it works on any motherboard without a driver upgrade) – nyanpasu64 Jun 29 '14 at 03:48
  • Read [Different ways to determine CPU speed in Windows XP or in Windows Server 2003](http://support.microsoft.com/kb/888282) and [CPU frequencies shown in System property page do not match](http://support.microsoft.com/kb/2878342). – Cristian Ciupitu Jun 29 '14 at 04:26

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