What goes inside a smartphone's processor?

Qualcomm recently unveiled a new processor called as Snapdragon 778G. This processor is rated to be higher or as good as their 800 series processor which are deemed to be their flagship line-up. But why is that? How do companies manage to churn out heaps of processors every year? Let's find that out today

Let's talk about ARM first. They developed something known as RISC (Reduced Instruction Set Computing) architecture which has a lot of differences with the architecture followed by Intel and AMD with better power consumption rates. Gradually the industry is moving towards RISC / ARM based machines as Apple showed off their superior M1 chip capabilities. You don't need to know more about this, just know that the way the computing works in your regular / legacy laptops and your phones are quite different thanks to different computing instructions given to your processor. If you are interested in the history of these processors, then I highly recommend watching this video

ARM designs processor chips and sells these layouts to companies like Qualcomm and Mediatek who use these designs and come up with competitive processors, these are then manufactured by a company called TSMC (most of the time). These were highly used for small computers that didn't need to handle huge loads of tasks. Eventually, we are now in the time where these processors are out performing Intel and AMD CPU's in a lot of day to day applications. So let's learn a bit about what goes inside these processors which we get in our smartphones.

Most smartphone processors today have something known as "cores" in it. These cores handle a set of tasks given by the user / an application. To make use of these cores efficiently by the processor, we follow something called as big.LITTLE architecture.

The layout is some what similar to this. In a big.LITTLE architecture, we have "big" cores and "LITTLE" cores. Big cores are performance oriented which handle huge complex tasks leading to more power consumption. When the user is using small tasks based applications then he need not need high performance, so this is where little cores are used. A processor can have any number of performance cores and efficiency cores making it the job of Qualcomm and others to design the best layout for their processors. ARM most of the time designs these cores and sells it over to others to design and manufacture processors. (A side note, big.LITTLE is kind of getting replaced with something known as DynamIQ which allows for more flexibility in number of cores in a processor)

If you are wondering what a CPU scheduler is, it is a "logical decider" of sorts to decide which tasks are to be handled by which core. There are a bunch of these but the most used one is EAS ( Energy Aware Scheduler). There is a fantastic research paper on applying ML algorithms to make tasks scheduling much better with lesser power consumption. I highly recommend you to take a look into it.

Now that I have explained the theory parts, lets look into what cores your snapdragon 778G has. The cores are structured in this manner

1 -> Cortex A78 based Kryo 670 prime at 2.4 GHz

3 -> Cortex A78 based Kryo 670 gold at 2.2 GHz

4 -> Cortex A55 based Kryo 670 silver at 1.9 GHz

Now let's ignore all that Kryo 670 terms for a second. All you need to know is that Cortex A78 is a high performance based core while A55 is an efficiency focused core. Now here's what Snapdragon 888 has

1 -> Cortex X1 based Kryo 680 Prime with up to 2.84 GHz

3 -> Cortex A78 based Kryo 680 Gold with up to 2.42 GHz

4 -> Cortex A55 based Kryo 680 Silver with up to 1.8 GHz

Again, let's ignore all the kryo terms and the clock speeds. We get 1 Cortex X1 based core which ( obviously ) would be faster than an A78 based core. With only 1 majorly different core at its core (haha get it?) we can see that why the 778G is as good as a 888 processor. So if you are someone eyeing on a flashy new smartphone to get this season, hopefully this article helps you in your buying decisions :p

Bonus: Apple's A14 bionic chip has 2 High performance cores and 4 energy efficient cores. Despite having only two of those we all know how hard it trashes android smartphones in few applications. This gives us a huge perspective of how important software optimization is despite immense hardware innovation.

Credits: The cover photo is by Jessica Lewis from Pexels and the cores details in 778G and 888 is from [Wikipedia](en.wikipedia.org/wiki/List_of_Qualcomm_Snap..5G(2021)