Terry Myerson, Executive Vice President, Windows and Devices Group, Microsoft. (GeekWire Photo /Todd Bishop)

After several days of dodging questions about the performance impact of patches designed to fix the Meltdown/Spectre chip design flaws, Microsoft acknowledged Tuesday morning that Windows Server is now slower for certain types of applications thanks to the patches.

“Windows Server on any silicon, especially in any IO-intensive application, shows a more significant performance impact when you enable the mitigations to isolate untrusted code within a Windows Server instance,” wrote Terry Myerson, executive vice president for the Windows and Devices group, in a blog post released Tuesday. The post comes after representatives of the company declined to comment to GeekWire regarding the performance impact of the patches Monday, which are clearly affecting a swath of enterprise computing organizations.

The two vulnerabilities take advantage of a 20-year-old design flaw in modern processors can be “mitigated,” the word we’re apparently using to describe this new world in 2018 where servers became somewhere around ten to 20 percent less effective for several common workloads. While the principal companies involved have been coy about the performance impact that results from the patches recommended to deal with these issues, others have provided more details about exactly what type of applications are affected.

“We’re … committed to being as transparent and factual as possible to help our customers make the best possible decisions for their devices and the systems that run organizations around the world. That’s why we’ve chosen to provide more context and information today and why we released updates and remediations as quickly as we could on Jan. 3,” Myerson wrote in the blog post. The companies involved in the Meltdown/Spectre patches first learned of the vulnerability last June, and worked under embargo to develop patches rolled out last week.

Myerson also noted that Windows PC users with recently purchased systems probably won’t notice much of a performance impact from the patches pushed out to Windows users last week, but people with older Windows 10 hardware, and people with Windows 8 or Windows 7 machines, will likely see a performance hit.

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