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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  • Netmsm - Monday, November 8, 2021 - link

    @Wrs Assume we give you this, just drop AMD related things.
    Let's focus on performance per watt of new Intel Architecture. I asked some questions about this which is a pertinent topic to this article but you dodged. Just talk about 241 watt being sucked by 12900k :))
  • ajollylife - Sunday, November 7, 2021 - link

    To be fair Intel's def not perfect. The i225v lan bug comes to mind
  • DominionSeraph - Saturday, November 6, 2021 - link

    When Intel doesn't have this issue it is AMD.
    Intel demands validation and spends hundreds of millions on engineers to help motherboard manufacturers fix their issues before release because they realize that the motherboard is an INSEPERABLE part of the equation. You can fanboi all you want over the CPU, but if there are no good motherboards you have a terrible system.
    AMD just dumps their chip on the market, leaving the end-user with a minefield of motherboard issues among every manufacturer.
    When Intel has the problem solved but AMD doesn't, it's an AMD issue.
  • Qasar - Saturday, November 6, 2021 - link

    DominionSeraph have you tried this on a different x570 board ? it COULD be just that board, as was already stated. i have been running a 5900x now for about a week, and no issues at all with disk access, its the same as the 3900x i replaced, and im using an asus x570 e-gaming board.
    maybe take a step back, realize that its NOT an amd issue, but a BOARD issue. to be fair, intel has had its own issues over the years as well, while you see them as perfect, sorry to break it to you, but intel also isnt perfect
  • Netmsm - Sunday, November 7, 2021 - link

    Oh I got it, the fact that you're encountering unusual issues, despite myriads of people who haven't complained of the same problem you have, means that AMD got many incompatibility issues.
    That's a brilliant reasoning which brings us to a pure conclusion: AMD is bad. We're done here.
  • Dug - Monday, November 15, 2021 - link

    "Note Intel doesn't allow "dog sh1t motherboards" to happen, especially at the $300+ price point. That makes it an AMD issue."

    You obviously haven't looked at or experienced the issues that plague many motherboards. Maybe just read some reviews or visit manufactures forums to get an idea of how bad it is before making such a naïve statement.
    It has more to do with the manufacturer of the board than the CPU.
    That is like saying nvidia doesn't make crap video cards. Well you need to look at all the failures by each manufacturer, not nvidia itself.
  • madseven7 - Saturday, November 6, 2021 - link

    You put that chip in an ASROCK motherboard. That's the reason for the issues.
  • xhris4747 - Tuesday, November 9, 2021 - link

    Lol 😅
  • FLORIDAMAN85 - Friday, November 12, 2021 - link

    I, too, have made the error of purchasing an ASRock board.
  • mode_13h - Saturday, November 13, 2021 - link

    So far, my ASRock Rack server board is still going strong.

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