Microsoft is expected to begin rolling out OTA updates for Windows 8.1 and 7 devices with security fixes on Patch Tuesday and before rolling out new cumulative updates, Microsoft detailed the impact of Meltdown and Spectre patches on older devices in terms of performance. It lies in AMD's documentation for its CPUs, Microsoft asserts, which is erroneous in some respects, and whatever differences there are between the documents and reality of AMD's processors are serious enough to have caused affected machines to fail to boot.
The good news is that for Windows 10 PCs with modern Intel processors, the Windows security patches plus the additional firmware updates necessary for addressing a specific variant of the Spectre vulnerability won't have a big impact on performance. Although it had initially been said that only Intel chips presented with the flaw, those made by ARM and AMD are also vulnerable.
Based on users' reports, the problem appears to affect some older CPUs built by AMD, including Athlon and Sempron, although so far there's been no official summary of what all has been affected.
In other words, this is AMD's fault (at least according to Microsoft). Most of its processors manufactured after 1995 include the Meltdown and Spectre vulnerabilities.
Microsoft said that it is still testing the speed impacts of updating systems, and it doesn't have concrete numbers yet.
For the full details on the block put on the update, check out this Microsoft support post.
Microsoft has said that to receive any future security updates on any Windows system, KB4056892 must be installed. Hardware OEMs and OS manufactures have banded together to release patches to help mitigate the effects of any attacks based on Meltdown or Spectre, although some of those patches have been disastrous.
The question many will be asking is whether the performance hit is a price with paying for the security mitigation. This is an architectural issue and it can't simply be fixed with a patch.
Microsoft has released a patch that will be delivered in your normal update cycle for your laptop.
Some Microsoft users who have installed the latest Windows security update have experienced freezing on devices with AMD processors, Microsoft disclosed in a recent update on its support site.
Any organizations preparing to issue the January cumulative patch from Microsoft may prefer to wait until they get one that doesn't leave some AMD systems unbootable.