Do CPU Microcode Updates Need to be Reinstalled if Win is Renstalled?

hsehestedt · 13 Mar 2018

Microsoft has been releasing some of Intel's CPU Microcode updates to patch Spectre flaws as part of KB4090007. This update has to be downloaded and installed manually from the Windows Update Catalog - it won't just download automatically through Windows Update.

I'm not really familiar with Microcode updates. Is the Microcode update something that Windows applies or loads like a driver each time Windows is booted or is it permanent like a firmware update?

In other words, what I really want to know is whether I only need to install this once for my system or will I need to reinstall it if I reinstall a clean copy of Windows?

Bree · 14 Mar 2018

hsehestedt said:

Is the Microcode update something that Windows applies or loads like a driver each time Windows is booted or is it permanent like a firmware update?

Some microcode updates are supplied as a bios update from the manufacturer, other are loaded at boot by the OS.

This KB4090007 from Microsoft installs a file named mcupdate_GenuineIntel.dll in System32 which Windows loads at boot. So yes, you'll need to reinstall it after a clean install.

hsehestedt · 14 Mar 2018

Thanks. I very much appreciate your taking the time to answer this for me.

Bree · 14 Mar 2018

hsehestedt said:

Thanks. I very much appreciate your taking the time to answer this for me.

You're welcome.

I have a personal interest in this as my OEM is not planning to issue a new bios for my older machine and MS have not (yet?) issued an update for my particular CPU.