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

johnpd · 30 Aug 2018

It installs and checks your system to see if it has a fix to apply to your particular PC. If not, then no change is made.

JohnD

Steve C · 30 Aug 2018

KB4100347 appears under Programs & Features / Installed Updates but not under Settings / Windows Update / View Update History.

Is this normal and why doesn't this update appear in both lists?

VBF · 30 Aug 2018

Steve C said:

KB4100347 appears under Programs & Features / Installed Updates but not under Settings / Windows Update / View Update History.

Is this normal and why doesn't this update appear in both lists?

Are you sure? It appears in both places on mine but when you look at it in View Update History, it's under "Quality Updates" with the carat (arrow) pointing down thus:

KB4100347 Intel microcode updates for Windows 10 v1803 - January 8-image.png

Steve C · 30 Aug 2018

VBF said:

Are you sure? It appears in both places on mine but when you look at it in View Update History, it's under "Quality Updates" with the carat (arrow) pointing down thus:

I just uninstalled and reinstalled the update and it now appears in both lists. I note the Quality Updates list shows 50 updates as it did before reinstalling KB4100347 when it should have increments to 51. Is the Quality Update list limited to 50 entries? It was full of MS Office 2010 updates since I recently had to reinstall Office.

VBF · 30 Aug 2018

Steve C said:

I just uninstalled and reinstalled the update and it now appears in both lists. I note the Quality Updates list shows 50 updates as it did before reinstalling KB4100347 when it should have increments to 51. Is the Quality Update list limited to 50 entries? It was full of MS Office 2010 updates since I recently had to reinstall Office.

Short answer - yes! If you get to 50 entries for any of the update histories, it rolls over so you get a "first in, first out" situation. This is particularly noticeable with the Windows Defender updates.

They all appear to reset to zero when you get a feature update ie, from 1709 to 1803. That makes sense as the updates before the Feature Update were effectively for an earlier version of Windows 10.

Phone Man · 30 Aug 2018

All my systems are AMD so I uninstalled this Update and it no longer is offered to me in WU.

All is good.

Jim

Tonyb · 30 Aug 2018

is on my other system its AMD has not heart one thing

andyouf · 31 Aug 2018

Hi, I have five questions.

I received a BIOS update. I was told that KB4100347 would only apply its ucode if that is newer than on the BIOS level. As best practice should I uninstall that KB411347 then hide it or is that a waste, especially since new updates will be coming? I figure it would just reinstall KB4100347 even with an equivalent BIOS patch. Anyway I almost want to roll back the update just to see the BIOS update change it. (Edit: okay that is what I did. Haven't done BIOS yet. CPU-Z validation still shows it patched but HWINFO shows it back at the old ucode. Surprisingly even if I check for updates WU doesn't want to reinstall KB4100347. Maybe it just takes time). Will it not download KB4100347 once I update the BIOS if it is not newer? If the patch versions are equivalent will the BIOS version take precedent? I take it this is something I will need to keep checking with my OEM as this will be updated. Do I still need InSpectre?

Does a BIOS update cause any decrease in performance like the OS level updates do? Mine says "released for Spectre." I was told Spectre has a higher impact than Meltdown; don't know if that comparison is just with OS level fixes.

Just to be clear. Meltdown is patched at the OS level using ucode from Intel and Spectre can be mitigated at BIOS or OS level using Intel's ucode or does Spectre need both levels? InSpectre says "This system's Intel processor provides high-performance protection from the Meltdown vulnerability" which makes me think it does not need a patch. But that is confusing because I also thought Meltdown didn't have to do with the processor.

Does uninstalling an update also uninstall any updates that came after that one?

How can I tell which Spectre version patch I have? CPU-Z validation doesn't seem to be accurate because it said I was still patched at CVE-2017-5715 even after I uninstalled the ucode. I have now installed the BIOS update and it is back at the ucode the OS had updated the CPU to but I don't know if that will continuously change or if there are Spectre patch versions.

I ran a bench in CPU-Z to compare the before and after. Don't know if that will tell me anything.

Oh to anyone who needs it this looks helpful.

winactive · 31 Aug 2018

It looks like Microsoft have botched the update (KB4100347) this has led to it being offered to machines that do not require it. Basically it is a .dll update. As I've repeated endlessly, the uCode will be ignored unless it is NEWER than the one contained in your BIOS. CPUs have errata, so uCode is almost always used to fix this. Spectre is a chip flaw (design errata) this is why the mitigations REQUIRE uCode to be implemented. You can check with your OEM; I would say the OEMs lack of coordinated effort and response is WHY we are getting these updates. InSpectre is incomplete as a way of checking mitigation (that in a perfect world will be applied AUTOMATICALLY) via OS updates INCLUDING uCode fixes.

HWiNFO in my experience shows the active uCode. It shows from UEFI only, it shows updated via .dll it even shows the software updated version that you can use for dev testing.

Performance decreases are where you see them. There is no definitive degree or measure as to how much a slowdown you will see. It is task related. The tasks it affects may not be present on your machine or you never run software that is sub-optimal (code can be re-written or recompiled to avoid speculative execution).

Meltdown mitigation does not require uCode. Spectre variants have a performance impact. As I've said before, you cannot quantify exactly how MUCH this will affect YOU unless you quantify it. Meltdown is an OS flaw based on how the CPU handles system memory and application memory. Meltdown and Spectre

Uninstalling updates impacts updates that use that update as a pre-requisit.

Edit: the last article is only helpful if you understand that almost any information you read on the threats can be outdated. You must check the date of the articles and of the last update of the sites or articles it links to.

andyouf · 31 Aug 2018

Okay so according to the first page of this thread ucode version=spectre patch version for my CPU.

that in a perfect world will be applied AUTOMATICALLY) via OS updates INCLUDING uCode fixes

I thought OS updates also did do ucode fixes it was just a more inefficeint way to execute them?
I sort of regret uninstalling KB100347 as I don't want that to mess with any future updates. As far as I can see that contained a revision to 0x24 which is also where the BIOS update took me so I doubt it will reinstall.

There is no definitive degree or measure as to how much a slowdown you will see.

But BIOS level ucode adjustments are less impactful than OS level, right? Why is it better if you have a BIOS patch? Code that avoids speculative execution, isn't that a bad thing. Doesn't speculative execution greatly increase performance in everything. Even the browser?

So Meltdown could potentially be fixed by MS since it is an OS flaw? Has MS released any KB mitigations for meltdown yet?