Microsoft testing Windows 10 patch that minimizes Spectre performance impact

Microsoft rolled out new Windows builds that feature the retpoline optimizations to minimize the performance hit of the Spectre mitigations that were rolled out last year to address security vulnerabilities in AMD and Intel CPUs. Starting with the Windows Insider Preview builds version 18272, "retpoline" is enabled for Windows on certain devices, this should improve performance of Spectre variant 2 mitigations.

Retpoline was developed by Google engineers and has been reviewed by Microsoft to ensure compatibility with Windows.

At runtime, any indirect jumps in software are identified and fixed in memory following a kernel examination. Not all programs can make use of retpoline sequences in every instance, but it is enough to make Spectre effectively useless for malicious users.

The end result of Microsoft's latest performance update shows up to 25 percent improvements in application launch times. Storage throughput has increase 1.5- times in DiskSpd benchmarks, while networking has also seen drastic improvements on Broadwell CPUs.

Full details at TechSpot. This fix will be rolled out to mainstream Windows 10 builds via KB4482887.

Documentation from Microsoft confirms retpoline is compatible with all AMD CPUs and Intel CPUs prior to the Skylake architecture. Skylake and newer had better mitigation and were less affected by this performance hit.