AMD Ryzen reported Safe against Spectre 2 on Windows 10 Redstone 5

PCs with AMD processors blocked for Win10 build 17035

It seems that AMD Ryzen systems on the current preview of Windows 10 Redstone 5 are patched against Spectre. The Ryzen processors are not affected by Meltdown vulnerability, and now InSpectre reports that they have been updated with new features that allow the operating system to eliminate the Spectre variant 2 as well.

Ryzen Systems are Spectre Protected on Windows 10 Redstone 5, AMD Testing Microcode in Insider Program?

Early this year, Intel released its first microcode updates for its processors to mitigate against the Meltdown and Spectre vulnerabilities. But just a few days after the release, the company had to withdraw the updates as they caused “higher system reboots.”

Now the improved BIOS and firmware updates for Intel Skylake are available again. They are even being rolled out directly via Windows updates so that users don’t have to install them manually.

AMD Ryzen vulnerable to Spectre 2

AMD, on the other hand, has yet to provide a new microcode update. The company has admitted that it’s affected by Spectre v2, but claims the risk is close to zero.

Recently, however, users at Planet3DNow forums discovered something unexpected as part of the report from the InSpectre tool. The tool evaluates Windows hardware and software, and reports whether the in-built system is protected against Meltdown and Spectre or not.

An AMD Ryzen-powered system on Windows 10 v1709 is usually protected against Meltdown (since AMD processors are not affected), but it’s vulnerable to Spectre as there is not yet a microcode update, and therefore no performance hit. So far, so normal.

However, a forumite by the name of ThePowerOfDream got a status on their Ryzen system, saying it’s protected against Spectre. The user participates in the Windows Insider Program and is currently on Windows 10 Redstone 5 Preview Build 17618.1000.

AMD Ryzen Spectre protected on Windows 10 Redstone 5

It looks like AMD is testing its microcode updates in the Insider Program. What’s interesting, though, is that HWiNFO64 reads the same microcode version (μCU 8001136) for both Windows 10 RS5 and version 1709 Fall Creators Update.

You could suspect that there is an error in the InSpectre tool, but that seems unlikely because the Microsoft Powershell script also marks the Ryzen under Redstone 5 as patched and protected against Spectre.

The other possible explanation would be something like “Retpoline for Windows.” Microsoft has been working on integrating Retpoline into Windows 10, which is basically a workaround mitigation technique introduced by Google to protect against Spectre variant 2.

In short, it’s not clear at the moment what exactly is behind this. If you’re already using Windows 10 Redstone 5, do share your own insights in the comments below.