Conclusion

Intel Core "Alder Lake" is a very interesting processor architecture, and given Arm SoCs have had Hybrid architectures for over eight years now, the latest Intel chips can only be considered a step in the right direction. While there's people claiming that Intel only introduced E-cores to dial up core counts, we think there's actual tangible benefits to this new approach, and we're just at the beginning of this journey. The "Gracemont" E-cores operate in an optimized performance/watt band, and turned out to be a lot faster than expected, enabling Intel to sneak up on AMD's high-core count "Zen 3" processors. Under the right circumstances, the new cores can be made to contain lightweight background tasks, and contribute to reduced system power consumption. This, however, comes with the requirement of software optimization (as with Arm big.LITTLE in its initial days back in 2013).

The main reason Intel is recommending Windows 11 over Windows 10 has to do with changes to the thread scheduler, the piece of Windows that decides which core(s) to run any of the hundreds of concurrently running threads on. Intel has worked closely with Microsoft to make sure the new operating system queries all the right capabilities and is set up to benefit from "Thread Director"—a dedicated piece of silicon in the processor that recommends how to distribute threads to Windows. The big difference compared to mechanisms like CPPC2 "Preferred Cores" is that Thread Director runs continuously on the CPU (it's independent and doesn't use up CPU time) and monitors the situation with millisecond accuracy. CPPC2 is only a static recommendation that can't change while the system is running. In their press briefings, Intel clarified that Thread Director uses a pre-trained AI model internally. It does not "learn"—the model and its decisions are fixed and deterministic. Going forward, Intel does have the ability to update that model, possibly through microcode updates wrapped into motherboard BIOS updates. I think it should also be possible to distribute those changes through Windows Update for those motherboards that no longer receive BIOS updates (in a couple of years). To the best of my knowledge, nothing is set in stone yet regarding updates, so we'll have to be patient.

Windows 11 also comes with some improvements to its API for software developers to use, so they can tell the operating system whether something is a background thread, important, or even time-critical or not. Much of this functionality has existed in Windows for years, so it's not like Windows 10 is totally unable to make such scheduling decisions.

In our testing, aggregated across all tests, we find that Windows 11 is on average 6.5% faster than Windows 10, but there's a lot more to this. Synthetics like SuperPi and wPrime love Windows 10 because they're not optimized for modern Windows in any way, and for whatever reason, Thread Director misdirects wPrime workloads to the E-cores. On Windows 10, wPrime traffic somehow does get sent to the P-cores, where we see a massive performance gain. Considering Windows 10 doesn't interface with Thread Director at all and Windows 11 does, this would suggest that the issue lies with Intel's Thread Director, not Windows 11 itself. We also tested with the E-cores disabled completely, and Windows 10 is slightly faster than Windows 11 even here, although the newer OS gains massive ground.

Cinebench R23 sees absolutely no difference between the two operating systems regardless of whether we toggle the E-cores on or off. The benchmark simply uses all cores available and scales nicely. Ditto with Blender and V-Ray. Corona renderer seems to have a big problem with Windows 10, where the scheduler is sending traffic to the E-cores exclusively and the P-cores sit idle. The E-Core disabled performance of both operating systems is the same. With Windows 11 and E-cores enabled, Thread Director is working its magic, propelling the i9-12900K into the same league as the Ryzen 9 5950X. Windows 10 seems to play well with KeyShot, although Windows 11 is slightly faster.

Windows 10 remains poorly optimized for both game and software development on Alder Lake, with scheduler misfires seen in both Unreal Engine 4 bake lighting and Visual Studio compilation. It's only when we disable E-cores and force P-cores into play that we see tangible performance benefits. You're much better off with Windows 11 here. These two tests are also good examples that show why simply disabling E-cores is not the perfect solution, as the E-Core active test results are clearly faster than those with them disabled. There isn't much to report with web-browsing, as Alder Lake is already the fastest chip in any configuration. AI/ML is another mixed bag. Our Image Classification benchmark is being wrongly scheduled to E-cores on both Windows 10 and Windows 11, so E-Core disabling is needed for both. DNN training on Tensorflow works equally well on both operating systems. Both seem to work fine with scientific simulation tests.

Photoshop CC is relatively less parallelized and works equally well on both operating systems. Disabling E-cores ekes out a tiny bit more performance, but there are at least no major scheduler flaws. We're also happy to report that Premiere Pro CC works equally well on both operating systems, and the software is able to benefit from E-cores. Other productivity apps, like 3DF Zephyr, Tesseract OCR, etc., play well on both operating systems. MySQL, on the other hand, is a huge failure on the Hybrid architecture on both operating systems, which has disabling E-cores help in a big way. What's also interesting is that we see Windows 10 being significantly faster than Windows 11 here—surprising results for the world's most popular database server software. 7-Zip is well optimized for Alder Lake on both operating systems. Media encoding is another interesting mix. AV1 encoding works equally well on both Windows 10 and 11, while HEVC and H.264 are running better on Windows 11.

As we mentioned in our main review, gaming is still a lightly parallelized workload that favors brute IPC above all. There are optimization issues specific to certain games even on Windows 11, which are only precipitated in Windows 10. This is mainly the case when the OS scheduler is sending work to the lower-IPC E-cores. In the 720p academic resolution that highlights CPU-level bottlenecks, the trends favor Windows 10 with E-cores disabled as the fastest configuration. Even enabling E-cores doesn't put Windows 11 at any advantage from its more advanced scheduler.

1080p is the most popular gaming resolution, and we see a similar mixture of results to 720p, with both operating systems generally performing better with the E-cores disabled. There are a couple of cases, such as DOOM Eternal, Battlefield V, and RDR2, where Windows 11 with E-cores disabled comes out on top. The 1440p resolution where our GeForce RTX 3080 is made to work for a living shows similar trends, although the gaps between the various configurations are slimmer as the bottleneck shifts toward the GPU. At 4K UHD, the bottleneck is squarely in the hands of the GPU, making it a free for all between all modes. Surprisingly, Windows 11 in its default configuration (with E-cores enabled) comes out on top across most tests.

Overall, Alder Lake represents an advancement in processor design, and we're forced to recall many of the teething problems we faced with newer processors some 18 years ago—yeah, we were still grown up nerds back then. Features like HyperThreading and multi-core were new. OS schedulers and software became aware, and began benefiting from these. Games were slower to leverage parallelization even back then, but eventually caught up. In today's context, eight P-cores with insane IPC/clocks is all a game really needs, but developers will begin to see the value in E-cores for all the lightweight tasks, such as audio mixing or the network stack, under others. Windows 11 will certainly get better as a gaming OS with time, but we feel Windows 10 is the better OS for gaming right now, even on Alder Lake. There's also reports that Alder Lake's Hybrid architecture is breaking certain DRM solutions, such as older versions of Denuvo, rendering many games unplayable. In that sense, Windows 10 with E-cores enabled emerges as a safe bet. It's still faster than competing Ryzen processors at gaming due to the sheer IPC uplift of the "Golden Cove" P-cores.

So the decision to upgrade to Windows 11 should depend a lot on what you mainly do with your PC. Quite a few productivity apps are able to leverage the Hybrid architecture, and will benefit from Windows 11. Quite a few are penalized for it, but the solution isn't quite running Windows 10, but disabling E-cores, or manually adjusting the affinity of those apps. With gaming, Windows 10 seems to have a distinct advantage with E-cores disabled, more so because it doesn't have compatibility issues. If you're a gamer, stick with Windows 10 until you're compelled to upgrade. If you do more than just gaming, consider Windows 11, and toggle the E-cores on or off based on your requirements. What's probably the most important takeaway from this article is that Windows 10 works very well with Alder Lake despite the lack of support for the Hybrid architectures or Thread Director. In the vast majority of cases, you'll barely notice any difference between Windows 10 and Windows 11, so it comes back to whether you can you live with the Windows 11 start menu changes.