Microsoft has begun issuing patches for the Spectre and Meltdown security flaws afflicting most systems that run Windows. Older AMD systems, however, seem to have problems with the updates — reports of BSODs and update failures have been common, and some AMD users have been forced to reinstall Windows to successfully boot into an operating system.
Microsoft has released a statement to address the issue, blaming the problem squarely on AMD:
Microsoft has received reports of some AMD devices getting into an unbootable state after installation of recent Windows operating system security updates. After investigating, Microsoft determined that some AMD chipsets do not conform to the documentation previously provided to Microsoft to develop the Windows operating system mitigations to protect against the chipset vulnerabilities known as Spectre and Meltdown.
AMD, for its part, doesn’t deny Microsoft’s statement. It told Gizmodo it’s aware of the problem affecting “older generation processors” and is working with Microsoft to find a solution. After several days of AMD users reporting blue screens and bricked computers, Microsoft suspended the delivery of the following updates to AMD systems:
Another problem? In some cases, antivirus software is triggering BSODs once these patches are applied. You won’t be patched for Spectre and Meltdown until your antivirus is properly patched. Information on which antivirus solutions are patched and which are not is available here.`
The performance impacts of Meltdown and Spectre have been uncertain since they surfaced, but we’re beginning to see some hints about what things look like. First, while Meltdown can have a negative impact on servers and possibly some I/O workloads, the overall consumer hit seems small on current CPUs (it is not clear if older machines with different Windows variants are hit harder by Meltdown or not).
Unfortunately, the Spectre patch variants also carry their own risk of performance impacts. As we discussed in our recent explainer on speculative execution, Microsoft is now advising its customers and users that the patches to deal with Spectre can cause significant performance drops, especially for PCs with Haswell or previous Intel processors running Windows 7 or Windows 8.1. It is not clear how hard these regressions hit AMD chips and this is one area where we can’t lean on the idea that Intel and AMD will see the same results. Intel, for example, is vulnerable to Meltdown (and Meltdown can hit some server workloads) while AMD is not.