Samsung highlighted the performance of Galaxy S6 at its launch this year, which is no wonder. After all, the S6 processor is manufactured using the most advanced 14nm FinFET technology among mobile phone processors, which has obvious advantages over the 20nm Snapdragon 810 processor. How strong is this new processor? Please follow us to make a preliminary exploration.
The biggest highlight of the 7420 processor is that Samsung's own 14nm FinFET process is used. This process is one of the most advanced mobile phone processors at present - TSMC's 16nm process has not yet achieved mass production, while the 7420's competitor Snapdragon 810 processor still uses the 20nm process. From the perspective of the value of the process, the smaller the better, The smaller the distance between transistors, the lower the energy consumption and the stronger the performance. However, if the distance between transistors is too small, leakage current will occur between different parts of the chip. To solve this problem, the FinFET process will add a thin layer of silicon "fin" between the two conduction channels.
FinFET electron microscope photos released by Intel
FinFET (Fin Field Effect Transistor) is a new complementary CMOS transistor. Fin means fish fin. According to the similarity between the shape of the transistor and the fish fin, FinFET was invented by Hu Zhengming of the University of California, Berkeley. Its working principle is to change the transistor from a traditional planar structure to a 3D structure, which can control the circuit on and off at both sides of the circuit. This design can greatly improve circuit control and reduce leakage current, At the same time, the gate length of the transistor can be greatly shortened.
The first company to commercialize FinFET technology is Intel, which launched the 22nm FinFET process in 2011. At present, semiconductor manufacturers including Samsung, TSMC and Global Foundries have actively engaged in the research and promotion of FinFET.
As we all know, for the same processor architecture, lower power consumption means lower heat generation. If the power consumption allows, the frequency can also be increased as much as possible, or valuable power can be saved at the same frequency. The Exynos 7420 processor has certain features for the above.
The Exynos 7420 has no particularly revolutionary architectural progress. It still uses the four core Cortex-A57+four core Cortex-A53 large and small core architecture from ARM and the Mali-T760 GPU. If you want to know which mobile processor on the market is most similar to it, it is naturally applied to some versions of Galaxy Note 4, and it has learned from Exynos 5433.
Although ARM has just released the latest high-performance CPU architecture Cortex-A72, it is still unrealistic for Samsung to produce mass production products immediately. It is also normal to use the A57+A53 design to balance power consumption and performance. In principle, mild background applications will be handed over to the A53 core for processing. When high performance is required, The A57 will be put into operation, and the Exynos 7420 naturally supports GTS (Global Task Scheduling), that is, the eight cores will be put into operation at the same time, as well as the dynamic core voltage frequency adjustment function.
Of course, the Exynos 7420 also adds AArch64 to ARM. Although theoretically all A53 and A57 CPUs should have support for AArch64, Samsung's Exynos 5433 is artificially limited to AArch32, which means that it does not have 64 bit computing capacity at present.
Of course, there are few 64 bit optimized apps on Android at present, but at least the number is increasing. The native ART mode of Android 5.0 also directly adds 64 bit computing support. So when the Android 5.0 operating system is also running and 64 bit support is enabled, processors with 64 bit computing capabilities such as Exynos 7420 will have obvious performance advantages.
Thanks to the progress of the manufacturing process, Samsung was able to further increase the maximum main frequency of the Exynos 7420 A57 CPU to 2.1GHz. Compared with the 20nm process Exynos 5433 A57, the maximum main frequency of the A57 was increased by 200MHz to 1.9GHz. The maximum main frequency of the GPU was increased from 700MHz to 772MHz from 5433. The overall increase in frequency was about 10%, which naturally can lead to performance improvement.
However, the biggest improvement of Exynos 7420 over Exynos 5433 is in memory bandwidth and GPU performance.
The Exynos 7420 is Samsung's first processor that uses LPDDR4 memory. LPDDR4 memory has a 32-bit dual channel design, and the memory frequency has reached 1552MHz. In other words, the peak memory bandwidth of the Exynos 7420 has reached 24.8GB/s (25.6GB/s here, which should be an error).
This increase in memory bandwidth can naturally lead to a very significant performance improvement, which Samsung seems to have not yet met. Therefore, the 7420 processor has achieved the largest GPU performance improvement since the Exynos 5 series processors, including the number of cores and the dominant frequency. On the Exynos 7420, Samsung has reduced the number of GPU cores from the usual 6 cores among the 5 series processors (Exynos 5410 In addition, it uses PowerVR SGX544 MP3 GPU from Imagination, which is a three core design) and has been upgraded to an eight core design.
The improvement of the GPU is naturally beneficial and harmless for driving the 2K resolution screen on the Galaxy S6 and S6 Edge, and the progress of the process allows Samsung to reduce the voltage of the GPU when it runs at 700MHz by 200~300mV. Samsung once claimed that the new process can reduce energy consumption by 35%, and the energy saved is likely to be used to support the two new GPU cores.
When using Fun Rabbit to compare the performance scores of Galaxy S6 and Exynos Galaxy Note 4, it is not difficult to find that S6 is far superior to Note 4 in 3D graphics performance, and the screen resolution of both is 2560 × 1440. Although the performance scores may not fully represent the actual experience, the performance improvement reflected from this is real. In addition, the power of LPDDR4 memory is also reflected in the score run. As for the CPU performance improvement, it is expected - after all, the main frequency is higher and the process is more advanced, which is no surprise.
With improved performance and reduced energy consumption, Samsung's efforts on 14nm have naturally paid off, The strong performance of the Exynos 7420 also gives Samsung more confidence in abandoning the Qualcomm Snapdragon 810 processor this time. Although the 7420 and 5433 have no particularly strong improvement in CPU performance, from the perspective of the GPU, it is certain that the S6 2K screen can provide a better experience than before.
As for Samsung and Qualcomm mobile processors, which have been competing for a long time, Samsung won this time, and Samsung's strength is likely to last until next year, because Qualcomm will not be able to get a CPU with a process below 20nm until at least the end of 2015.
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