When Intel officially announced Alder Lake to the media, they had a slide stating that the 12th Gen processors would run best on Windows 11.
Even prior to the official announcement, there were little tweets in the rumour mill that Microsoft and Intel have been collaborating behind the scenes to make Intel’s new big.LITTLE architecture run at its most optimal on Windows 11.
This piqued my curiosity about the performance differences of the new Intel chips between Windows 10 and Windows 11.
Initially, I only intended to do a performance comparison test of games between Windows 10 and Windows 11, since Yahoo Gaming SEA focuses a lot on popular games and esports titles.
However, I noticed an odd CPU behaviour during my testing of the 12th Gen CPUs on Windows 10, which prompted me to change my approach in reviewing the i9-12900K and the i5-12600K.
In fact, if you are really interested to know about the raw performance that the 12th Gen CPUs are capable of, there are reviews and comparisons already available to the public from various media outlets for your consumption.
Now, let’s get to the meat of the article.
Two different types of CPU cores
Most of Intel’s 12th Gen models come with two different types of CPU cores, the P-cores (Performance cores) and the E-cores (Efficiency cores).
Both the i9-12900K and the i5-12600K that were tested in this article contain a combination of these cores. The P-cores are the powerhouse of the chip, being able to boost up pretty high in clocks, while also having multithread enabled on them.
The E-cores, however, have low boost clocks with no multithreading enabled, but are extremely power efficient.
To take advantage of these cores, Intel has implemented something called the Thread Director. To explain it in the simplest way possible, it is able to let the operating system know which are the P-cores and which are the E-cores, and what each core’s individual load is.
It essentially “suggests” to the operating system on which core is free, which thread can be used or freed up, which core is able to handle the programmes that are running on the system etc, be it a demanding programme or something as simple as a web browser.
The Thread Director essentially is the brain of the 12th Gen CPUs.
The Windows element
On Windows 11, this runs flawlessly for games and multitasking. Windows 11 is built with a scheduler that is able to recognise the information provided by the Thread Director, and delegates the running programmes accordingly to the relevant CPU cores.
The 12th Gen CPUs run symbiotically with Windows 11, creating the ultimate OS and platform that can multitask and run several programmes at once without much flaws.
On Windows 10 however, this isn’t present.
Instead of recognising the cores as performance vs efficiency, Windows 10 just recognises the cores as high-performance vs low-performance.
This method of core recognition is fine on older CPUs because all cores are mostly equal, with one or two cores being able to boost slightly higher than the average core clock present in the CPU (which will then be classified as the “high-performance” cores).
Windows 10 still thinks this is the case for the Intel 12th Gen CPUs, and will sometimes send programmes that are in need of a powerful CPU core to an E-core, leading to stunted performance due to the nature of the efficiency cores..
In my testing, I noticed that this is, more often than not, detrimental to users that game and have other programmes running at the same time, especially with a game capture or streaming software present.
The test bench is as follows:
Intel Core i9-12900K or Intel Core i5-12600K
2x 16GB TeamGroup T-Force Delta RGB 6000Mhz CL40 DDR5 RAM
Asus ROG Maximus Z690 Hero
Asus AMD Radeon 6900XT Strix
1TB Adata XPG GAMMIX S70 Blade PCIe Gen4 SSD
Seasonic Prime GX-1000 PSU
Asus Ryujin II 360mm CPU AIO Cooler with LGA 1700 bracket
Here are the graphs, one running on Windows 11, and one on Windows 10. Both will have results with only the game running, and a combination of the game + OBS. I will not put in the 1% low results for these graphs, because that is not the main point of focus for this article.
As you can see from the graphs, something is definitely up with how the chips are run on Windows 10.
Looking through the data from monitoring software like HWinfo and Rivatuner, it is very clear that when Windows 10 decides that the E-cores should take over the workload of running the game, the fps will dip significantly.
This mostly happens when there are multiple CPU intensive programmes running at the same time, in this case, OBS.
I also didn’t expect the programmes to remain running under the E-cores for that long. In older CPUs, Windows would usually just delegate whichever core that is available to a programme. Depending on the priority of the programme, Windows will attempt to push the more “important” programmes to the higher performance cores. So it is definitely a little weird that the games remain being run by the E-cores.
A not ideal solution
There is a solution for this anomaly — by manually assigning the programmes to run on specific cores of the CPU, but that is unnecessary and tedious work, especially for a PC user who is not into tweaking these things.
I have repeated the tests three times on three fresh installs of Windows 10 for the 12900K, and the results still remains the same.
I have tried replacing OBS with XSplit and Streamlabs OBS, and still face the same problem. I have also tried to open the usual programmes that a streamer would have, like Discord, Epic Games Store and Steam running in the background.
While it didn’t introduce any extra performance hit, it didn’t really fix anything either, so it was just for me to confirm it is a bad idea for a streamer to remain on Windows 10 if they want to upgrade to Intel’s 12th Gen CPUs.
The Windows 11 story
Performance on Windows 11 however, is immaculate.
Running multiple programmes at the same time introduces very minimal performance hit, and one could argue that the fps dips may be in the margin of error anyway.
You can clearly see the Thread Director and Windows 11 working in tandem here. Opening up more programmes also does not introduce any kind of performance degradation, because of the way the OS delegates the tasks to the 12th Gen CPU cores.
To be fair, the games tested here have generally high fps. Even with the performance hit from Windows 10, it is still in the playable range. The E-cores are strong enough to hold up the demands of high framerates.
If your games are GPU bound, this shouldn’t be an issue too. But compromising like this definitely isn’t ideal, especially when you’ve spent your hard-earned cash on Intel’s most capable consumer CPU up to date.
There is only one moral of today’s story:
If you want to use the 12th Gen CPUs to their fullest potential, you have no choice; you must use Windows 11.
Or you can choose to wait till Windows 10 releases a fix for this, but I highly doubt they will. Why allow users to use an old product when you can force them to use a newer one?
Dominic loves tech and games. When he is not busy being toxic in VALORANT or watercooling anything he sees, he does some pro wrestling.