The Intel 12th Gen Core i9-12900K Review: Hybrid Performance Brings Hybrid Complexity
by Dr. Ian Cutress & Andrei Frumusanu on November 4, 2021 9:00 AM ESTFundamental 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:
- Running dual monitors stops it
- Changing Windows Power Plan from Balanced to High Performance stops it
- 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.
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mode_13h - Saturday, November 6, 2021 - link
> A competent CEO wouldn’t have allowed this situation to occur.And you'd know this because... ?
> This is an outstanding example of how the claim that only engineers
> make good CEOs for tech companies is suspect.
You're making way to much of this.
I don't know who says "only engineers make good CEOs for tech companies". That's an absolutist statement I doubt anyone reasonable and with suitable expertise to make such proclamations ever would. There are plenty of examples where engineers in the CEO's chair have functioned poorly, but also many where they've done well. The balance of that particular assessment doesn't hang on Gelsinger, and especially not on this one issue.
Also, your liberal arts degree is showing. I'm not casting any aspersions on liberal arts, but when you jump to attack engineers for stepping outside their box, it does look like you've got a big chip on your shoulder.
Oxford Guy - Sunday, November 7, 2021 - link
‘Also, your liberal arts degree is showing. I'm not casting any aspersions on liberal arts’Your assumption about my degrees is due to the fact that I understand leadership and integrity?
mode_13h - Sunday, November 7, 2021 - link
> Your assumption about my degrees is due to the fact that I understand leadership and integrity?Yes, exactly. It's exactly your grasp of leadership and integrity that I credit for your attack on engineers stepping outside their box. Such a keen observation. /s
(and that's how you "sarcasm", on the Internet.)
kwohlt - Sunday, November 7, 2021 - link
I'm not sure how familiar you are with CPU design, but Alder Lake was taped in before Gelsinger took over. The design was finalized, and there was no changing it without massive delays. For the miniscule amount of the market that insists on AVX-512 for the consumer line, it can be implemented after disabling E Cores. AVX-512 just doesn't work on Gracemont, so you can't have both Gracemont and AVX-512 simultaneously. CPU designs take 4 years. You'll see the true impact of Gelsingers leadership in a few years.SystemsBuilder - Saturday, November 6, 2021 - link
MS and intel tried to sync their plans to launch Windows 11 and Alderlake at (roughly) the same time. intel might have been rushed to lock their POR to hit Windows 11 launch. There may even be a contractual relationship between Intel and Microsoft to make sure Windows 11 runs best on Intel's Alder Lake - Intel pay MS to optimize the scheduler for Alder lake and in return Intel has to lock the Alder Lake POR maybe even up to a year go... because MS was not going to move the Windows 11 launch date.Speculation from my side of course, but I don't think I am too far off...
Oxford Guy - Saturday, November 6, 2021 - link
Such excuses don’t work.The current situation is inexcusable.
SystemsBuilder - Saturday, November 6, 2021 - link
yes it is inexcusable BUT the Pat might not have had a choice because he does not control Microsoft.Satya N. would just tell Pat we have a contract - fulfill it!
We are not going to delay Windows 11 it's shipping October 2021 so we will stick with the POR you gave us in 2020!
Satya is running a $2.52 trillion market cap company current #1 in the world
Pat is running a $206.58 billion market cap company
so guess who's calling the shots.
Pat says "ok... but maybe we can enable it for the 22H1 version of win 11, please Satya help me out here..."
in the end I think MS will do the right thing and get it to work but it might get delayed a bit.
Again, my speculation. And again, I don't think I am far off...
Oxford Guy - Saturday, November 6, 2021 - link
The solution was not to create this incompetent partial ‘have faith’ AVX-512 situation. Faith is for religion, not tech products.The solution was to be clear and consistent. For instance, if Windows is the problem then that should have been made clear. Gelsinger should have said MS doesn’t yet have its software at full compatibility with Alder Lake. He should have said it will be officially supported when Windows is ready for it.
He should have had a software utility for power users to disable the small cores in order to have AVX-512 support, or at least a BIOS option — mandated for all Alder Lake boards — that disables them as an option for those who need AVX-512.
The current situation cannot be blamed on Microsoft. Intel has the ability to be clear, consistent, and competent about its products.
Claiming that Intel isn’t a large enough entity to tell the truth also doesn’t pass muster. Even if it’s inconvenient for Microsoft to be exposed for releasing Windows 11 prematurely and even if it’s inconvenient for Intel to be exposed for releasing Alder Lake prematurely — saving face isn’t an adequate excuse for creating a situation this untenable.
Consumers deserve non-broken products that aren’t sold via smoke and mirrors tactics.
SystemsBuilder - Saturday, November 6, 2021 - link
a couple of points:- yes it would have been better to communicate to the market that AVX-512 will be enabled with 22H1 (or what ever - speculating) of windows 11 but what about making it work with windows 10 and when... i mean the whole situation it's a cluster. I do agree that the current marketing decision under Pat's what and how to communicate to the market what is happening with Alder Lake and AVX-512 and Windows 10/11 could have been handled much, much better. the way they have done it is a disaster. it's like is it in or out i mean wtf. is it strategic or not. This market communicating, related decisions and what every new agreements they need to strike with Microsoft to make the whole thing make sense is on Pat - firmly!
- i am not blaming Microsoft at all. I am mostly blaming the old marketing and the old CEO - pure incompetence for getting Intel into this situation in the first place. I don't have all the insights into Intel's internals but from an outside perspective it looks like that to me.
Oxford Guy - Saturday, November 6, 2021 - link
Gelsinger’s responsibility is to lead, not blame previous leadership.Alder Lake came out on his watch. The AVX-512 debacle, communications and lack of mandated minimum specs (official partial support for the lifetime of AL in 100% of AL boards via BIOS switch to disable small cores) happened to while he was CEO.
The lie about fusing off happened under his leadership.
We have been lied to and spacetime can’t be warped to erase the stain on his tenure.