Windows Update KB4091663 slows down Ubuntu Guests

[Wildon]

Hi,

Yesterday I found that both of my Ubuntu guests (18.04 and 16.04) on my Windows 10 host was running very slowly. Since it was running fine the day before, I thought it may be some updates causing it. It turned out to be one of the Windows Update that was installed overnight, KB4091663, that was the culprit. I have no idea why it was causing the low performance. when I uninstalled the update, the issue went away. I am using VirtualBox version 5.2.18.

I thought to share it here so people with similar problem may find a this useful.

W.

[socratis]

I thought to share it here so people with similar problem may find a this useful.

Thanks for sharing. However, KB4091663: Intel microcode updates, according to the article (emphasis mine):

Intel recently announced that it has completed its validations and has started to release microcode for newer CPU platforms around Spectre Variant 2 (CVE 2017-5715: “Branch Target Injection”).

Slowing down is a side-effect that was expected in that case. That's how life is going to be from now on, slower.

[michaln]

Slowing down is a side-effect that was expected in that case. That's how life is going to be from now on, slower.

Especially for those with Intel CPUs, because if you have one of those, you can either run fast or safe, but not both.