Fundamental Windows 10 Issues: Priority and Focus

In a normal scenario the expected running of software on a computer is that all cores are equal, such that any thread can go anywhere and expect the same performance. As we’ve already discussed, the new Alder Lake design of performance cores and efficiency cores means that not everything is equal, and the system has to know where to put what workload for maximum effect.

To this end, Intel created Thread Director, which acts as the ultimate information depot for what is happening on the CPU. It knows what threads are where, what each of the cores can do, how compute heavy or memory heavy each thread is, and where all the thermal hot spots and voltages mix in. With that information, it sends data to the operating system about how the threads are operating, with suggestions of actions to perform, or which threads can be promoted/demoted in the event of something new coming in. The operating system scheduler is then the ring master, combining the Thread Director information with the information it has about the user – what software is in the foreground, what threads are tagged as low priority, and then it’s the operating system that actually orchestrates the whole process.

Intel has said that Windows 11 does all of this. The only thing Windows 10 doesn’t have is insight into the efficiency of the cores on the CPU. It assumes the efficiency is equal, but the performance differs – so instead of ‘performance vs efficiency’ cores, Windows 10 sees it more as ‘high performance vs low performance’. Intel says the net result of this will be seen only in run-to-run variation: there’s more of a chance of a thread spending some time on the low performance cores before being moved to high performance, and so anyone benchmarking multiple runs will see more variation on Windows 10 than Windows 11. But ultimately, the peak performance should be identical.

However, there are a couple of flaws.

At Intel’s Innovation event last week, we learned that the operating system will de-emphasise any workload that is not in user focus. For an office workload, or a mobile workload, this makes sense – if you’re in Excel, for example, you want Excel to be on the performance cores and those 60 chrome tabs you have open are all considered background tasks for the efficiency cores. The same with email, Netflix, or video games – what you are using there and then matters most, and everything else doesn’t really need the CPU.

However, this breaks down when it comes to more professional workflows. Intel gave an example of a content creator, exporting a video, and while that was processing going to edit some images. This puts the video export on the efficiency cores, while the image editor gets the performance cores. In my experience, the limiting factor in that scenario is the video export, not the image editor – what should take a unit of time on the P-cores now suddenly takes 2-3x on the E-cores while I’m doing something else. This extends to anyone who multi-tasks during a heavy workload, such as programmers waiting for the latest compile. Under this philosophy, the user would have to keep the important window in focus at all times. Beyond this, any software that spawns heavy compute threads in the background, without the potential for focus, would also be placed on the E-cores.

Personally, I think this is a crazy way to do things, especially on a desktop. Intel tells me there are three ways to stop this behaviour:

  1. Running dual monitors stops it
  2. Changing Windows Power Plan from Balanced to High Performance stops it
  3. There’s an option in the BIOS that, when enabled, means the Scroll Lock can be used to disable/park the E-cores, meaning nothing will be scheduled on them when the Scroll Lock is active.

(For those that are interested in Alder Lake confusing some DRM packages like Denuvo, #3 can also be used in that instance to play older games.)

For users that only have one window open at a time, or aren’t relying on any serious all-core time-critical workload, it won’t really affect them. But for anyone else, it’s a bit of a problem. But the problems don’t stop there, at least for Windows 10.

Knowing my luck by the time this review goes out it might be fixed, but:

Windows 10 also uses the threads in-OS priority as a guide for core scheduling. For any users that have played around with the task manager, there is an option to give a program a priority: Realtime, High, Above Normal, Normal, Below Normal, or Idle. The default is Normal. Behind the scenes this is actually a number from 0 to 31, where Normal is 8.

Some software will naturally give itself a lower priority, usually a 7 (below normal), as an indication to the operating system of either ‘I’m not important’ or ‘I’m a heavy workload and I want the user to still have a responsive system’. This second reason is an issue on Windows 10, as with Alder Lake it will schedule the workload on the E-cores. So even if it is a heavy workload, moving to the E-cores will slow it down, compared to simply being across all cores but at a lower priority. This is regardless of whether the program is in focus or not.

Of the normal benchmarks we run, this issue flared up mainly with the rendering tasks like CineBench, Corona, POV-Ray, but also happened with yCruncher and Keyshot (a visualization tool). In speaking to others, it appears that sometimes Chrome has a similar issue. The only way to fix these programs was to go into task manager and either (a) change the thread priority to Normal or higher, or (b) change the thread affinity to only P-cores. Software such as Project Lasso can be used to make sure that every time these programs are loaded, the priority is bumped up to normal.

Intel Disabled AVX-512, but Not Really Power: P-Core vs E-Core, Win10 vs Win11
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  • xhris4747 - Tuesday, November 9, 2021 - link

    They should use pbo it's fair to
  • xhris4747 - Tuesday, November 9, 2021 - link

    Is you using pbo some people are t using pbo which I think isn't fair because that i9 is oc to snot
  • EnglishMike - Thursday, November 4, 2021 - link

    It's not just the gaming world -- it's the entire world except for long-running CPU intensive tasks. Handbrake and blender are valuable benchmarking tools for seeing what a CPU is capable of when pushed to the limit, but the vast majority of users -- even most power users -- don't do that.

    Sure, Intel has more work to do to improve power efficiency in long running CPU intensive workloads, but taking the worst case power usage scenarios distorts the picture as much as you're claiming the reviewers are doing.
  • Wrs - Thursday, November 4, 2021 - link

    Can't calculate efficiency without scores. Also, well known that power scales much faster than performance. The proper way to compare efficiency is really at constant work rate or constant power.
  • blanarahul - Thursday, November 4, 2021 - link

    Sorry sir I can't. You haven't provided me the data for how much time each test took! Would you be so kind as to do that?
  • Netmsm - Thursday, November 4, 2021 - link

    Sorry, this is a direct link to Tom's bench:
    this is for "blender bmw27" in which both 12900k and 5950x finish the job around 80 seconds BUT 12900k sucks power for about 70 percent more than 5950x.

    you can find other benches here:

    I'm wondering why Ian hasn't put 12900k nominal TDP in results just like all other CPU's! When 10900k was released with nominal TDP of 125, Ian put than number in every bench while in reality 10900k was consuming up to 254 (according to the Ian's review)! When I asked him to put real numbers of power consumption for every test he said I can't because of time and because I've too much to do and because I've no money to pay and delegate such works to an assistant!
    But now we have 12900k with nominal TDP of 241 which seems unpleasant to Ian to put it in front of it in results.
  • Zingam - Friday, November 5, 2021 - link

    Last gen game. How about glquake?

    1 billion computing devices and just a few million game units sold? What does it mean? Gamers are a tiny but vocal minority.
    If they bring this performance at 5W on low and 45W on high then its good for majority of people. This is just a space heater.
  • Gothmoth - Friday, November 5, 2021 - link

    so throwing more cores on a game that can´t make use of them is usless thanks for clarifing that.... genius!!

    when a 5600x is producing 144 FPS and a 5950x is producing 150 FPS the 5600x is the clear winner when it comes to efficency.

    now try to cool the 12900K in a work environment with an air cooler.
    i can cool my threadripper with a noctua aircooler and let it run under full load for ours.

    i am really curious to see how the 12900k will handle that.

    i am not an amd fanboy. i was using anti-consumer intel for a decade before switching to ryzen.
    i would us intel again when it makes sense for me (i need my pc for work not gaming).

    but with this power draw it does not make sense.
  • Wrs - Saturday, November 6, 2021 - link

    The 12900k is fine with a Noctua D15 in a work environment. Doesn't matter if you're hammering it at 95C the whole time, the D15 doesn't get louder. But it's no megachip like a Threadripper. For that on the Intel side you'd wait for Sapphire Rapids or put up with an existing Xeon Gold with 8-32 Ice Lake cores at 10nm.
  • Netmsm - Saturday, November 6, 2021 - link

    How would it be justified to buy Xeon Gold in place of Threadripper and Epyc?!

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