Microsoft temporarily blocks AMD Meltdown and Spectre patches

Wednesday, 10 Jan, 2018

The good news is that for modern PCs running Windows 10, most consumers won't notice a significant difference.

Meanwhile, Microsoft is dealing with the aftermath of Meltdown and Spectre patches that produced errors that disabled AMD PCs for some users. "In the longer term, we have started experimenting with techniques to remove the information leak closer to the source, instead of just hiding the leak by disabling timers", blogged Mozilla software engineer Luke Wagner.

Microsoft said that newer personal computers will likely not have a perceivable performance dip. But as patches roll out, customers have begun to worry what the performance impacts might be, too. You do not need to apply these mitigations to isolate your Windows Server VMs from other VMs on a virtualized server, as they are instead only needed to isolate untrusted code running within a specific Windows Server instance. PCWorld's Meltdown and Spectre FAQ and our guide to keeping your PC safe from the CPU flaws have a lot of additional information.

AMD shares dipped 1.3 percent in pre-market USA trading.

Surface devices will also be patched, Microsoft said, beginning today. But Liverpool, England-based security researcher Kevin Beaumont, who's been tracking patches that are being issued to mitigate Meltdown and Spectre, says it's likely that Microsoft will issue another monthly patch release once it resolve the AMD problem. But the TL;DR is simple; the fixes impact system performance. If you're on an older machine, particularly a Windows 7 or Windows 8 one, then there's going to be some noticeable performance changes.

Currently, Microsoft supports 45 different releases of Windows. We will publish data on benchmark performance in the weeks ahead. Microsoft offers guidance for AMD/Windows users impacted by the situation in this post.

Initial estimations said the Linux Meltdown and Spectre patches would produce between 5% and 50% slowdowns, but further tests and benchmarks proved many claims exaggerated. 2015-era Windows 10 PCs with Haswell or older CPU might experience significant slowdowns. "This means the typical home and business PC user should not see significant slowdowns in common tasks such as reading email, writing a document or accessing digital photos".

Over the course of last week, it became apparent that many companies were affected. SharedArrayBuffer may return after the company is confident that it can't be used to stage an attack, according to Microsoft Principal Lead Program Manager John Hazen. This led to a flood of complaints on Microsoft's support forum, at which point Microsoft halted the patches. Intel's own findings largely confirm Microsoft's results.