Testing the Cortex-X2: A New Android Flagship Core

Improving on the Cortex-X1 by switching to the Arm v9 architecture and increasing the core resources, both Arm and Qualcomm are keen to promote that the Cortex-X2 offers better performance and responsiveness than previous CPU cores. The small frequency bump from 2.85 GHz to 3.00 GHz will add some of that performance, however the question is always if the new manufacturing process coupled with the frequency increase allows for better power efficiency when running these workloads. Our standard analysis tool here is SPEC2017.

Running through some of these numbers, there are healthy gains to the core, and almost everything has a performance lift.

On the integer side (from 500.perlbench to 557.xr), there are good gains for gcc (+17%), mcf (+13%), xalancbmk (+13%), and leela (+14%), leading to an overall +8% improvement. Most of these integer tests involve cache movement and throughput, and usually gains in sub-tests like gcc can help a wide range of regular user workloads.

Looking at power and energy for the integer benchmarks, we’re seeing the X2 consume more instantaneous power on almost all the tests, but the efficiency is kicking in. That overall 8% performance gain is taking 5% less total energy, but on average requires 2% more peak power.

If we put this core up against all the other performance cores we test, we see that 8% jump in performance for 5% less energy used, and the X2 stands well above the X1 cores of the previous generation, especially those in non-Snapdragon processors. There is still a fundamental step needed to reach the Apple cores, even the previous-generation A14 performance core, which scores 34% higher for the same energy consumed (albeit on average another 34% peak power).

Just on these numbers, Qualcomm’s +20% performance or +30% efficiency doesn’t bare fruit, but the floating point numbers are significantly different.

Several benchmarks in 2017fp are substantially higher on the X2 this generation. +17% on namd for example would point to execution performance increases, but +28% in parest, +41% in lbm and +20% in blender showcases a mix of execution performance and memory performance. Overall we’re seeing +19% performance, which is nearer Qualcomm’s 20% mark. Note that this comes with an almost identical amount of energy consumed relative to the X1 core in the S888, with a difference of just 0.2%.

The major difference however is the average power consumed. For example, our biggest single test gain in 519.lbm is +41%, but where the S888 averages 4.49 watts, the new X2 core averages 7.62 watts.  That’s a 70% increase in instantaneous power consumer, and realistically no single core in a modern smartphone should draw that much power. The reason why the power goes this high is because lbm leverages the memory subsystem, especially that 6 MiB L3 cache and relies on the 4 MiB system level cache, all of which consumes power. Overall in the lbm test, the +41% performance costs +20% energy, so efficiency is still +16% in this test. Some of the other tests, such as parest and blender, also follow this pattern.

Comparing against the competition, the X2 core does make a better generation jump when it comes to floating point performance. It will be interesting to see how other processors enable the X2 core, especially MTK’s flagship at slightly higher frequency, on TSMC N4, but also if it has access to a full 14 MiB combination of caches as we suspect, that could bring the power draw during single core use a lot higher. It will be difficult to tease out exactly who wins what where based on implementation vs. process node, but it will be a fun comparison to make when we look purely at the X2 vs. X2 cores.

Unfortunately due to how long SPEC takes to run (1h30 on the X2), we were unable to test on the A710/A510. We’ll have to wait to see when we get a retail unit.

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  • Kangal - Sunday, December 26, 2021 - link

    You keep hearing it because it is true. I didn't say the competitors lacked optimisation, but it's merely a difference of degree. No matter how hard Samsung can try, Apple will win by default simply because of those intangible advantages. Sometimes these are minor and meaningless victories, other times they are more pronounced and notable for users. But I digress.

    Sorry, you're wrong.
    Those were some of (if not the) strongest competitors against those respective iPhones. I challenge you to provide even better ones.

    I'm confident in this because I'm a nerd for these things. You can flip back to GSMArena and search for yourself. It is only to YOU that it LOOKS "random phones" because you're not as informed as I am, and secondly, because I tried to be unbiased and used diverse range of OEMs (Samsung, Sony, Google, ASUS). But there have been lots of interesting devices from the likes of LG, ZTE, Huawei, Xiaomi, etc etc over the years.

    I personally don't like the QSD 865. Sure it was faster than the QSD 855, but not by much, and it achieved it by using more power, generating more heat and throttling soon. The QSD 870 is a much much better implementation. Whilst the QSD 888+ is much much worse, as they doubled down to use even more power, generate more heat, throttle even sooner. Why did Qualcomm do this? Just to try and catch up to the Apple A13! Like it or not, Apple is two-generations ahead of the industry now, and that's why they've taken it easy with the designs on the A14 and A15.

    I suspected the QC 8g1 will be very similar to the QSD 888+, lackluster, and the independent reports that have been published recently shows its as bad as I estimated. So whilst there is a fairly big difference when going from the QSD 768G (best high-end) to the likes of the QSD 855 (worst luxury/flagship), there is very little difference in real-world use going from the QSD 855 to the QC 8g1 (best flagship). There's so much more to a processor than unrealistic synthetic benchmarks. So I recommend people to stick with their 2019 Samsung S10+, ASUS RoG 2, OnePlus 7t, and similar phones for another year. We will see a much larger improvement in 2023 with the Second-gen ARMv9 processors that were designed by the European Team. That will probably match or surpass the Apple A15 then, but it will leave Apple with a 18 month window to either: lose some ground, maintain it, or extend their lead. Time will tell.
    Reply
  • Qasar - Sunday, December 26, 2021 - link

    Kangal, you keep touting how great the iphone is over any android device, but the truth is, for the most part any apple product will ALWAYS be a niche product, for one simple reason, price. apple is just too expensive for most people. i work with about 50 people, and only 4 of them have an iphone, and only one of them have a mac of some sort, and its all because of price. one who currently has an iphone, is looking at an android based phone, all because apple is just too expensive for what you get. its not called the apple tax for nothing.... Reply
  • Kangal - Monday, December 27, 2021 - link

    I agree with you there.
    Apple is one/the most profitable corporation in the world. Their gaming division makes more money than PlayStation, Xbox, Nintendo, and Steam combined. That's why they don't want to move into AAA-Gaming and are very comfortable catering for Mobile Gaming, In-App-Purchases, with their 30% cut. Their telephone division sells only 20% of the worldwide phones, but they reap over 80% of all the profits in the whole market. The Apple Watch sells more watches than any other watch in the world, regardless if their smart or analogue. They have the highest Tablet sales in the iPad. And I believe the Apple TV sells one of the highest of all TV Boxes.

    Now if the issue is merely about money, then the solution becomes rather simple. If I told you, that 40 of your friends were going to receive iPhones (locked to them, so no resale) for FREE, and I also told you it comes with a $100 balance to spend on Apps. Well, then there's little argument to be made here.

    Ofcourse, we don't live in a vacuum. Price is important, so value for money is a reality we must consider. So that's the nuance. I can say iPhones are great and have many advantages, but I can also not use one personally, and not recommend one for people who are middle-class, poor, or budgeting.
    Reply
  • Qasar - Monday, December 27, 2021 - link

    have you SEEN the prices for their products ???????????????????????????? if they weren't the most profitable, some thing would be horribly wrong. doesnt change the fact, that apple is over priced for what you get.

    i bet quite a few of them, would say no thanks. some arent fans of apple at all. and would just use those as paper weights. i wouldnt use an iphone even if apple payed me to.

    " and not recommend one for people who are middle-class, poor, or budgeting. " so, you then go and pretty much insult them ? wow, get off your high horse. they dont buy apple products because they are over priced, some can afford them, but they dont buy them, as again over priced, and have better things to spend their money on.
    Reply
  • Kangal - Wednesday, December 29, 2021 - link

    Yes, I saw their prices.
    Some of the most expensive and over-priced products in the world, actually most, come from companies that are actually struggling financially. Apple is not. They are thriving.

    So for them to be able to price their products that high, AND, be very profitable says something about the product they are selling. Clearly hundreds of millions of buyers every year, they do not agree with you, they see the value with their product and it's services.

    I am not on a high horse, and frankly I don't think you know what you are talking about. Stating that someone is budgeting (rich or poor), or they are middle-class, or even if they are impoverished... IS NOT AN INSULT. It is not a joke, but a reality, some people can afford things others cannot. And for me to say, this product is not recommended for those people, that is very appropriate. It would be worse for me to say otherwise. Otherwise, it would be the case that yourself Qasar, is recommending that a person who is looking to buy a base-model Hyundai, you find it appropriate for them to also shop for an Audi.

    If you CAN afford an iPhone, AND, if you WANT the features/characteristics of an iPhone. Then buy an iPhone. That is all I'm saying. If you DON'T like the characteristics of an iPhone, shop around. If you CANNOT afford an iPhone, then it wasn't an option to begin with. Nothing controversial there.
    Reply
  • Qasar - Wednesday, December 29, 2021 - link

    " Stating that someone is budgeting (rich or poor), or they are middle-class, or even if they are impoverished... IS NOT AN INSULT " i showed some of them at work this, and they consider what you are saying as in insult to them, cause you ASSUME that that cant afford it, they can, but they wont spend that kind of money on a phone ( iphones cost at least 1k here.)

    " If you CAN afford an iPhone, AND, if you WANT the features/characteristics of an iPhone. Then buy an iPhone. " they CAN afford one, the do like the features and such of them, but as i said, WAY to expensive. not worth the price.

    "If you CANNOT afford an iPhone, then it wasn't an option to begin with. Nothing controversial there." the same can be said about your lame analogy between the hyundi and audi.

    bottom line STILL stands, apple products are overpriced. while others are willing to pay those prices, there are just as many who wont, who would rather spend that kind of money on more useful things then a phone, specially when from what i have seen, and heard, they will spend that kind of money, but then cant afford, or wont spend the extra 50 bucks or less to put that phone in a case to protect it from damage, which is ironic. i know quite a few out side of work, where with in a month, their brand new iphone, has a cracked screen, or some other damage.
    Reply
  • Kangal - Thursday, December 30, 2021 - link

    Well, the problem here is that you are wrong, but you are too narrow-focussed to understand. This will seem insulting to you, but it isn't my intention.

    I doubt you showed this comment to your friends. And even if you did, their reaction doesn't make you correct. If they WANT an iPhone, and they CAN afford it, but they CHOOSE to not buy one. Well, that's their choice. As I said above. There's nothing wrong or bad about that, I do not want to control people, I want people to make their own decisions with their own money.

    And the thing you also got wrong, is that I never said the iPhone is the best. You can read my comments over again. Apple does a lot of things great, and somethings they do best, but that doesn't make them "the best". Because what is "the best" depends on an individual perspective. As an analogy, someone might think their porsche is the best car in the world, for another person it might be their JEEP, and for someone else it might actually be a Subaru. All three are correct for different reasons: fastest, versus durable, versus versatile.

    The bottom-line is that, it is just YOU who subjectively FEELS like the iPhone is overpriced. Whereas, according to the world, it is not. The iPhone is the top selling phone model in the world. People all over the world are LITERALLY voting with their wallets for it, which means for HUNDREDS of MILLIONS they don't think it is overpriced (they justify its costs).

    Me?
    I (Kangal) personally don't use an iPhone, as there are phones better for my wants/uses/needs. So I can't justify the cost, even though I personally CAN afford one.... BUT! That doesn't mean I am going to lie and be an Android fanboy. I can admit Apple's innovation and truthfully respect iPhones, without needing to buy one. With that said, there is A LOT of things I do not like about them also.

    I think there isn't anything else needed to say on this subject. People can read all my comments, in context, for themselves.
    Reply
  • Qasar - Friday, December 31, 2021 - link

    " Well, the problem here is that you are wrong, " could say the same to you.
    " I doubt you showed this comment to your friends " i did, but i doubt anything i will say, will convince you other wise
    " If they WANT an iPhone, and they CAN afford it, but they CHOOSE to not buy one. Well, that's their choice. " the DO want an iphone, but YET again, they find they are not worth the price, as they find them too expensive.
    " The bottom-line is that, it is just YOU who subjectively FEELS like the iPhone is overpriced. " WRONG. most of the people i work with says the iphones are over priced, its not just me, why else do you think only 4 people have them ? but, hey if YOU feel 1k is not to much for a phone, then that is your view.

    " The iPhone is the top selling phone model in the world. " and part of that, is probably due to phone carriers offering subsidiaries for phones, at least they do here. but you get stuck with at least a 2 year plan with them, some times longer, bust those i work with, still wouldnt get one.

    " I think there isn't anything else needed to say on this subject. People can read all my comments, in context, for themselves. " agreed.
    Reply
  • Wereweeb - Tuesday, December 14, 2021 - link

    Now install a privacy-oriented open-source OS on the "supercomputer" you use to watch youtube.

    Oh yeah, no, your data is all going to Apple.
    Reply
  • dubyadubya - Tuesday, December 14, 2021 - link

    I'll switch to an iPhone when Apple lets me operate my phone my way and has the apps I need/want on their products. And the big one let me access the data on my phone without needing to install iTunes! Reply

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