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I was wondering if there are any downsides (even theoretical) to enabling Hardware Virtualization in the BIOS. I noticed that it is disabled by default, and perhaps it is that way for a reason although I can't think of a good one.

My computer is an Intel-based (i7 QuadCore) HP EliteBook laptop, but I'm more interested in the general case.

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up vote 7 down vote accepted

One reason is security.

Root kits could use it to gain higher access to hardware than OS. Setting it to disabled mitigates this risk (see analysis).

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Performance-wise? No.

Security-wise? See @Josip's answer (which I've upvoted, btw)

However, common malwares can't yet leverage the virtualization extension. And if you use your computer safely (e.g., run as a regular user instead of an administrator-level one), the risks are practically mitigated.

That said, if you want to run virtual machines, Virtualization Extensions (Intel VT-x or AMD-V) will help increase performance significantly.

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Hi Pepoluan, could you please provide some background or references in regard to your statement that performance is not affected? I don't have any specific reason to doubt but I believe this would be a better answer if it included an explanation. Thanks. – Marquez Dec 19 '14 at 20:57
It has been quite some time since I did the research (note the date of my answer), so unfortunately I can no longer find the reference. IIRC, it's a discussion topic in the Xen mailing list. – pepoluan Dec 22 '14 at 9:36

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