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Windows 11 Outperforms Linux With Alder Lake CPUs, Scheduler to Blame

Windows 11
(Image credit: Microsoft)

A report from Phoronix has revealed that Intel's Alder Lake CPUs perform much better in a Windows 11 environment than with Linux-based operating systems. The problem is related to issues with Linux's cluster scheduler, which isn't optimized for Alder Lake's hybrid architecture. That means that Alder Lake, which are now the new Best CPUs for gaming, are better suited for Windows 11 than Linux. That's somewhat surprising given that Linux typically outperforms all flavors of Windows. 

Phoronix tested using a Core i9-12900K and Windows 11 Pro, Ubuntu 21.10 plus Linux 5.16 git, Ubuntu 21.10, Ubuntu 21.1.0 plus Linux 5.15, Clear Linux 35250, and Fedora Workstation 35.

Phoronix tested the operating systems with a range of different benchmarks, including browser benchmarks, video encoding, image encoding, blender, and more.

Windows 11 Pro won 45% of the tests out of the six operating systems, making it the most optimal operating system for Alder Lake systems. 

Alder Lake Operating System Benchmark Score

(Image credit: Phoronix)

The Windows 11 victory is due to problems with the Linux scheduler and its interaction with Alder Lake CPUs. As a reminder, the Alder Lake chips consist of two different types of cores: The big and fast Performance cores (P-cores) are paired with a smattering of small and powerful Efficiency cores (E-cores) that chew through background processes with surprising speed. 

This Linux scheduler is designed to control multiple core clusters, but it wasn't designed to differentiate between different types of cores, like Alder Lake's P-cores and E-cores. Unfortunately, that means the scheduler is unaware of the performance differences between the cores, much like we see with Windows 10. As a result, the scheduler will send workloads to the E-cores that should be sent to the faster P-cores, and vice versa.

As you can see in our Core i9-12900K review, this same type of performance issue is present in Windows 10, and for similar reasons: In the end, Linux and Windows 10 will have to adopt a means to interact with Intel's Thread Director, which feeds the operating system with real-time telemetry so it can better schedule threads to the correct types of cores, to extract the best performance.

According to Phoronix, there's no current workaround to this problem (except for disabling the E cores entirely) for Linux. Hopefully, Linux 5.16 will introduce better compatibility with Alder Lake, but there's no guarantee when or if those changes will arrive.