Windows 11 vs 10: Intel CPUs apparently sluggish, and it's worse without Microsoft's help

Update: More related testing suggests Microsoft's Windows 11 is actually generally slower on Intel non-hybrid parts.

Intel moved to a hybrid x86 CPU design for its 12th generation of Core processors (Alder Lake). Not only that, but the company also made several other changes to other components too, dubbed the "Uncore" portion of the processor, also referred to as the System Agent, which includes the Northbridge. One such change is apparently causing various latency issues and sluggish performance in general on Intel's hybrid chips according to a report by YouTuber Tech YES City (TYC).

TYC, citing industry sources with knowledge of the matter, explains that the problem, apparently, is a consequence of the "I/O driver" of the uncore (System Agent) that was allegedly moved off the CPU on Intel's 12th Gen and 13th Gen chips.

Using latency tests, TYC shows that the problem is especially pronounced on Windows 10 in most cases. Although Windows 11 is not fully immune to these performance quirks, Microsoft and Intel's combined efforts on optimizing Thread Director for the hybrid processors do pay off in some of these cases, even though past gaming performance numbers have not suggested the same.

In the description of their YouTube video, TYC writes:

I always thought Intel's CPUs were snappy, in fact that were the snappiest of snappiest, even vs Ryzen, where AMD have improved a lot over the years with their latency. However with the advent of 12th gen Alder lake and 13th Gen i9-12900k and 13900K CPUs respectively, Intel took something AWAY, and that was they moved the I/O driver directly off the CPU (that's what I was told from multiple sources), and this was the exact reason why latency issues have been occurring on these CPUs for windows users

In order to test and understand the validity of the perceptive difference they felt, TYC compared their 10th Gen Core i9-10850K (Comet Lake-S) with the Raptor Lake-S i9-13900K (13th Gen). In some cases like DPC (Deferred procedure call) latency, the performance is bad on both Windows 11 and 10, though still, the Windows 10 system does do worse. This makes sense as DPC is directly related to driver handling efficiency and some part of the I/O is involved.

Other cases like dragging and dropping MP4 files and rapidly opening MP3 files in Adobe Premiere Pro also exhibit poor showing on the part of the newer Raptor Lake CPU.

Some of the performance differences seen here may also have to do with the core-to-core (c2c) latency differences in Raptor Lake compared to Comet Lake.

As you can see in the images above, courtesy of AnandTech (1,2), the c2c latency varies quite a lot on the hybrid Intel 13900K compared to the 10900K. The c2c on the 10900K varies from as low as 5.6 ns to as high as 23.8, while that on the 13900K is anywhere from 4.0 ns to 53.9, and the latencies between the E-cores are especially bad.

Source and images: Tech YES City (YouTube)