The new phone Samsung Galaxy S4 is the first to wear a eight core processor, the Exynos 5 Octa (which the Korean company itself manufactures). Therefore, it's one of the main attractions of the new device, which is designed and built to dominate the Android phone market.
This SoC, which was presented at the CES fair in Las Vegas as we already indicated in Android Help, uses the architecture ARM big.LITTLE, so it has two sets of four cores, one Cortex-A7 and another Cortex-A15, which are used according to the needs at any given time (the first for the less demanding and the second, to give the maximum). The eight cores cannot be used at the same time and, as Samsung itself has indicated, the use of this technology allows save battery preventing maximum power from being used in applications that do not require it.
Here we leave you a video in which you can check how it works the new Exynos 5 octa that includes the Samsung Galaxy S4.
Demonstration video:
Processors, a constant evolution
And this can be seen in the advancement of the Exynos family, which began with models with a 90nm manufacturing technology and now uses 28nm. This results in processes running with greater efficiency and speed, and also with much better dissipation. In addition, the new processor that includes the Exynos 5 octa includes technology HKMG, so it is capable of save up to 70% energyHere's another video to learn about the efficiency of this new SoC.
Additional video:
Big.Little operating modes and their impact
The architecture big.LITTLE It contemplates three forms of work that determine performance and consumption:
- Cluster migration: Cluster A15 or A7 is activated depending on the load. This is the default mode in the 5 Exynos Octa of the Galaxy S4, prioritizing savings whenever possible.
- Nuclei migration: allows you to granularly change only the cores that are overloaded, combining, for example, an A15 with three A7s. improve efficiency by avoiding sudden jumps between clusters.
- Heterogeneous Multiprocessing (HMP): The planner distinguishes A15 and A7 and mixes both in parallel depending on the task. This is the most flexible approach, since adapts the hardware to each thread.
To unlock the second and third mode a DVFS driver (Dynamic Voltage and Frequency Scaling) capable of precisely deciding which type of core is appropriate at any given time and a kernel scheduler that understands cluster heterogeneity.
Real efficiency: Linux kernel, DVFS and support
The big.LITTLE theory is brilliant, but its effectiveness depends on the software. On the Galaxy S4 with Exynos 5 Octa, Linux kernel and driver support determine the available scheduling methods. If the scheduler treats all cores equally, heterogeneity cannot be exploited properly and only the first one is used. cluster migration, less fine than HMP.
The result is that the fiancée Energy Efficiency It may be lower than expected in some scenarios, not because of the silicon, but because of the software layer. Some of the advanced developer community (the so-called ROM "cooks") has addressed this. compiling kernels with more modern schedulers and refined DVFS, achieving more granular utilization of A7 and A15. In stock ROMs and kernels, these changes are not always present.
It is important to understand that, although the platform is capable of great savings, the key is that the operating system activates the appropriate modes and assign the loads with intelligence to each core.
LTE and Galaxy S4 variants: Exynos and Snapdragon
The Galaxy S4 was marketed in two configurations main ones that differ in the chipset: the variant with Octa 5 Exynos 5410 and the variant with Qualcomm Snapdragon 600The latter integrates a widely used LTE modem, while Samsung announced that the Exynos 5 Octa supports LTE in multiple bands. The regional choice of one or another SoC was linked both to production capacity as well as the availability of modems and bands in each market.
These differences also impact the GPU: the Exynos edition uses PowerVR SGX544MP3, while the Snapdragon edition uses Adreno 320. In both cases the Galaxy S4 has 2GB of RAM and expandable storage, so the day-to-day experience depends more on the usage profile than the name of the chipset.
Performance: Synthetic tests and everyday use
In the first public benchmarks, the Galaxy S4 with Exynos offered outstanding figures: in Quadrant results were seen around 12.726 points and in AnTuTu around 27.417, beating several rivals with hardware from the same era. These metrics serve as a reference for peak performance, although they do not replace the sensations of use or sustained efficiency.
The important thing is that the Exynos 5 Octa, with its A15 cores for heavy load and A7 for light tasks, responds with solvency in demanding apps and keeps power consumption in check when the active system is well-tuned. With mature kernels and DVFS, the combination can approach the ideal behavior of big.LITTLE, balancing power and autonomy.
One of the great additions of the new Samsung Galaxy S4 is its new processor that, in addition to the different functionalities that this new terminal offers, with it is capable of offering good performance in all types of applications and, furthermore, consuming much less energy. A totally different inclusion and development, without a doubt… now the performance tests will decide. By understanding the big.LITTLE modes, the role of kernel and DVFS, and the coexistence of Exynos and Snapdragon variants, it's easier to understand why the Galaxy S4 can shine in benchmarks and, at the same time, rely on software to achieve the promised efficiency.
