ARM Processors – Whats so special about them

In short, it’s the power (watts) to efficiency ratio compared to other processors. If you want to understand why, read on….

Keeping this article AS simple AS possible, modern day desktop processors, the likes of those produced by Intel and AMD, have become larger more complex beasts over time. Either their size has physically increased (look at the AMD Threadripper) or the components inside have had to be shrunk down, allowing more to be crammed inside the package (The nanometer nm die process).

In the x86 Intel processor architecture, specific areas of each core were designed to perform certain specialized instructions incredibly efficiently… though there is a downside to bolting on all these specialized units. Running such a large CPU core with bits just waiting for a suitable time to be used, is quite a power hungry task, and be it that you are using the core for very simple or specialized instructions takes up 1 clock cycle and 1 amount of whatever power is required. Other data waiting to be processed either is pushed to another core if available/code allows, or into a queue waiting to be served when the core is free again.

The thing is, not every bit of data that needs to be worked on requires a complex instruction set or even the full grunt of GHz offered by such a powerful CPU. So why have high GHz CPU’s chewing up power, when only a low power core will suffice?

ARM’s approach – DynamIQ

ARM have always pushed to make their CPU’s power efficient, indeed its part of the ethos that ARM processor were built upon, however ARM started to look at finding ways to split their multi-core CPU’s into Heavyweight and Lightweight cores. Heavyweight cores handle intensive tasks or specific instructions, usually at a higher GHz and like traditional processors consume more power. Then you have Lightweight cores to handle smaller or non-specialized instructions at a much lower energy requirement. Indeed applications can be moved between cores as necessary to maximize performance/energy use as needed or applicable.

SOURCE - ARM Youtube Channel

This approach has provided huge benefits in areas such as Smartphones, where battery life is a real limitation, allowing manufacturers to produce similar sized phones, with improved battery life, better performance, whilst still utilizing the same size capacity batteries.

Datacentres & the cloud

Large Enterprise wants to scale this type of performance/energy saving gain to  data centers, with the obvious benefit being millions of dollars saved in energy costs, without any loss of performance. Indeed its actually possible to create a processor package that watt for watt of power, returns much more processing power than current x86 processors offer in a like for like sized package. As you can imagine, with their huge data centers, companies like Microsoft, Google, Amazon find this incredibly appealing.

Take a look at 2 existing processors. One processor is 389 millimeters square in size, uses 120 watts of power and returns 1900Mhz of processing grunt. Then we have a tiny 24 millimeter square processor, running at 0.6 watts with 800Mhz of grunt.  When you calculate the energy (watts) to how many FLOPS (floating point operations per second), the smaller CPU returns 80x more FLOPS per watt than the larger CPU.

Indeed, because of its size, you could cover the surface area of the larger CPU with the smaller 24mm2 cpu cores and return much faster overall performance at a lower wattage, than the larger CPU is capable of.

So AMD DynamIQ is a blend between larger and smaller cores to return maximum performance.

Where is AMD heading with their CPU’s

Looking through information AMD have made available to the public, the suggestion would be that AMD are aiming to make more densely packed CPU cores with a mic of both Heavyweight and Lightweight. Add on to this improved management of data to/from memory and how its allocated out through the CPU’s cores (because transferring data around a computer takes time and energy too). This would seem to be part of the push with the 8CX Snapdragon that Qualcomm have built, which is designed to tackle the laptop market initially, though later generations may move towards the desktop market (or perhaps a mobile phone/desktop hybrid).

Additionally, AMD have also been advertising jobs for more specialists on GPU cores. The implication you could draw from this, is that AMD wish to push themselves further into competition against Intel, Nvidia and AMD in the lower end of the Graphical market through improving their chips GPU performance/compatibility. It would at least seem a logical leap, though time will tell.

What about other companies?

Obviously Intel and AMD aren’t just sitting around watching what’s happening, they too have noted this shift, run the maths and are working on their own products to compete, though, they are tied into the x86 architecture, which will carry some limitations or complexities to produce lower power systems of a Heavyweight/Lightweight design.

There are other technologies in the offing Intel and the likes are looking at such as 3D stacking, which is in effect building the memory and other such components directly into the CPU, resulting in quicker memory access and lower time/energy to communicate with components around the traditional style computers of today.

SOURCE - Intel Foveros

Again, time will tell what successes each of these technologies bring with them.

The future for ARM

With the release of the 8CX later this year, Qualcomm and ARM have a lot prove to the market and whilst they cannot compete with the x86 architecture at the moment, especially in the gaming/graphics market, however with more AMD processors in the world than any other kind, there’s a lot of development, interest and money being thrown into this CPU.

Just in case you’re wondering how many ARM processors there are in the world, in 2017, that figure was at 100 billion according to ARM https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/inside-the-numbers-100-billion-arm-based-chips-1345571105.

Indeed its believed that Apple are planning to move their entire desktop/laptop systems to run on their own in-house AMD chips by 2020. So there is a real potential shift that AMD might become the next big name in laptops/desktops in the very near future.

With the uptake by Microsoft to build and maintain Windows on ARM, which is capable of running some/most x86 code, ARM has a a real leg up to crack the business market. If they can win the data centers, gaming market, as well as hold their own against Intel and AMD, then next time you buy yourself a computer, it might just be an ARM processor you find inside.

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