KB4100347 Intel microcode updates for Windows 10 v1803 - January 8 Win Update

pietcorus2 said:

I have both keys on "3" in regedit.
What does this mean ? ( Protected/not protected )...............?

Look at this post
3 = Disable for both Spectre v2 and Meltdown.
If you μcode is the appropriate one, according to Intel, then you're fine.

@eXtremeDevil
According to Microsoft

FeatureSettingsOverride values:
8 = Enable All (Speculative Store Bypass together with Spectre Variant 2 and Meltdown)
3 = Disable both Spectre Variant 2 and Meltdown
2 = Disable Meltdown (Kernel VA Shadow)
1 = Disable Spectre Variant 2 (Branch Target Injection)
0 = Enable Spectre Variant 2 and Meltdown

FeatureSettingsOverrideMask value is always 3

Why it was set to 0 by the update, I have no clue. It could be because your CPU is not affected by the new Speculative Store Bypass aka Spectre variant 4.

eXtremeDevil said:

How do you know that??

If that's the case, I guess 8 or 0 will have the same performance impact?

And finally, what's the New production MCU rev column in the intel document? Is that for net manufactured cpus?

As I said, I don't know it. I said "could be", as not all CPUs are affected by all vulnerabilities.
8 means all three, 0 means only the first two.
New production mcu means, the new μcode intel produced to address the new vulnerabilities spectre variant 3a and spectre variant 4.

You're most welcome.
Hope to have shed some light on all this vulnerabilities issue.

Ground Sloth said:

I see a lot of people saying to use HWiNFO to determine the microcode update revision that is being used. You can also check in the Windows Registry.

https://superuser.com/a/895447

You can use that too, for the CPUID. It's just HWInfo has everything in one place!