“The price-performance ratio has nothing to do with friends. It’s not just a slogan. It’s not just a slogan, but Redmi K40’s determination to build the 2021 flagship price-performance king.” As Redmi’s new year masterpiece in 2021, it is also a killer with the “K” prefix The person in charge-the Redmi K40 series was unveiled on the 25th as scheduled .
This year’s Redmi K40 series strategy has undergone considerable changes. This time, the “entry model” mid-range machine that used to be constrained and deliberately chosen to form a distinction is gone-it is directly the “flagship + flagship” dual flagship lineup.
Simply put, it is different from the previous positioning of the mid-range standard version and the flagship Pro version. The entire product series of the Redmi K40 is without exception, all flagships: the K40 series does not have a middle cup, and all series are equipped with Snapdragon 8 series flagship processors; The flagship direct screens of the whole series have exactly the same standard specifications; not only the processor and screen upgrades, but also the audio and video, experience, craftsmanship and other aspects are also aligned.
This trick is really fierce. The fundamentals that separate Redmi K40, Redmi K40 Pro, and Redmi K40 Pro+ from each other are only the difference between the processor platform models of Snapdragon 870 and Snapdragon 888, and the camera difference between IMX582, IMX686, and Samsung HM2. , Can be described as “medium cup rises to big cup, big cup rises to super big”, forcing itself to upgrade the entire product line.
So what is the specific gap between Snapdragon 870 and Snapdragon 888? What are the differences in the imaging experience of different models of the main camera? Next is our detailed evaluation of Redmi K40 and Redmi K40 Pro.
2. Appearance: Microporous, thin and light, the most beautiful Redmi phone ever
The three models of the Redmi K40 series have the same appearance. They all use a 6.67-inch hole-digging full screen with a resolution of 2400*1080, which is what we often call 1080P resolution, and the refresh rate is increased to 120Hz. The screen panel uses E4 luminescent material, 1300nit peak brightness, and supports 360Hz touch sampling rate.
At present, 5G mobile phones are generally heavy and heavy, and the Redmi K40 series has optimized the internal structure of the fuselage, controlling the weight of the whole machine to 196g, and the thickness of the fuselage is as thin as 7.8mm. This is a rare time since the birth of the Redmi K series that has a thin and light feel. It coincides with its elder brother, Xiaomi, and puts on a “light outfit” posture.
Prior to this, the side-mounted capacitive fingerprint module was usually designed in a groove, which would damage the visual perception. What is quite surprising this time is that the Redmi K40 series truly integrates the side capacitive fingerprint module with the power button, and there is even no difference in color, and the integration is stronger.
The back of the fuselage is not a flat surface. It adopts a continuous curvature G3 curve design. The streamlined micro-arc middle frame transition is more natural. Compared with the previous tough and straight male works, it is much softer and gentler.
The redmi K series’ rear-camera shapes are consistent and highly recognizable, especially the silhouettes of the previous “coin-operated machines” are quite distinctive. This work has a tendency to unify the design language of Xiaomi and Redmi families. The camera part adopts a racetrack design, the main camera and the telephoto macro lens are arranged on both sides, the ultra-wide-angle lens and the microphone are in the middle, and the curvature of the peripheral camera cover is consistent with the racetrack curvature, giving more in-depth thinking about the design .
There are 6 symmetrical openings on the top of the fuselage, which sum up the upper speaker and infrared remote control as a whole. Obviously, the Redmi K40 series uses stereo dual speakers.
3. About Snapdragon 870 and Snapdragon 888: match new and old! Dimensionality reduction takes over the misplaced competition
The Redmi K40 is equipped with the Snapdragon 870, and the Redmi K40 Pro and Redmi K40 Pro+ are equipped with the Snapdragon 888. Behind this combination is the new and old combination of Qualcomm’s flagship core.
Snapdragon 870 takes over the misplaced competition
Remember that the Snapdragon 7 Series, Snapdragon 6 Series and other sub-flagship and high-end product lines have encountered dislocation competition impact from the MediaTek Dimensity family and Samsung Orion platform around 2020. Under pressure from rivals, Qualcomm chose to package the highly acclaimed flagship platform Snapdragon 865 overclocking processing into an 870 to take the battle again.
The Snapdragon 870 on the Redmi K40 is the second iteration of the Snapdragon 865. The overall specifications are basically the same as those of the Snapdragon 865 Plus after the initial iteration of the Snapdragon 865. The main change is the use of an enhanced Kryo 585 CPU core. Improved by 100MHz, 360MHz higher than Snapdragon 865, can be regarded as the ultimate overclocking version of Snapdragon 865.
In other respects, the Snapdragon 870 is still manufactured in a 7nm process, integrating a large core + three middle cores + four small core CPUs, Adreno 650 GPU, FastConnect 6800 wireless subsystem, Spectra 480 ISP, Hexagon 698 DSP, and external Snapdragon X55 The 5G baseband supports the 5G Sub-6GHz and millimeter wave frequency bands that are truly facing the global market, with a maximum download rate of 7.5Gbps and a maximum upload rate of 3Gbps.
It is worth noting that although some opinions regard the Snapdragon 870 as a “Snapdragon 865++”, this is not accurate. The Snapdragon 870 is more like an extremely optimized upgrade of the Snapdragon 865, rather than an enhancement on the basis of the Snapdragon 865+. The most typical is that the wireless module of the Snapdragon 870 is not the FastConnect 6900 on the Snapdragon 865+, but the FastConnect 6800. The latter is the native solution of the Snapdragon 865. The biggest difference between the two is whether it supports W-Fi 6E or not.
This also makes Redmi K40 lose support for W-Fi 6E from the hardware level. However, Wi-Fi 6E is an enhanced version of Wi-Fi 6. The biggest improvement is the introduction of support for the 6GHz frequency band, 59 more continuous channels, and the peak speed in short-distance scenarios is much faster. Of course, Wi-Fi6E still needs the cooperation of terminals and routers to play its full strength.
Snapdragon 888 is the flagship core of regular iteration
The specifications of the Snapdragon 888 must be very familiar to everyone. It is manufactured using a brand-new Samsung 5nm process. The CPU still has eight cores, but it has upgraded a new architecture layout, especially the world’s first super core of ARM. Architecture Cortex-X1.
The main frequency of the X1 core of the Snapdragon 888 is the traditional 2.84GHz, and there are three performance-level cores of the A78 architecture, all at 2.40GHz, and four energy efficiency cores of the A55 architecture, all at 1.80GHz. It also integrates Adreno 660 GPU. Qualcomm claims a 35% increase in graphics rendering performance and a 20% increase in energy efficiency. At the same time, the display technology has been greatly enhanced to support 144Hz high refresh rate/high frame rate, true 10-bit HDR, and so on.
There have been some controversies surrounding the Samsung 5nm process adopted by Snapdragon 888 before, and we have a detailed interpretation of this:
There has never been a fixed industry standard for semiconductor process technology, and how to design and name it is entirely up to each individual. Since TSMC’s 16nm and Samsung’s 14nm began to be completely messed up, the two companies often started various brainstorming operations in order to better look at the indicators. For example, when TSMC’s 16nm was improved, it was called 12nm, which appeared to be more advanced than Samsung’s 14nm.
The process of different wafer factories is indeed difficult to compare from the micro level. For example, the Samsung process technology used by Snapdragon 888 is different from the well-known TSMC process technology-this is especially obvious after 10nm. For example, Samsung chose EUV (Extreme Ultraviolet) lithography for a few layers at the 7nm node, while TSMC’s first two generations of 7nm processes used immersion lithography with a wavelength of 193nm.
Although their names are “7nm process”, but the appearance is always very different. Moreover, Samsung’s subsequent 6nm and the 5nm chosen by Snapdragon 888 are actually the same-generation evolution of the 7LPP process, while TSMC is not. Therefore, the technical path and iteration method of the two have long-term differences. It is currently impossible to judge from the micro level. Samsung’s 5nm and TSMC’s 5nm are better, and there is no difference.
In short, due to the differences in different standards, different iteration rhythms, and different naming rules in the process of different wafer manufacturers, it is difficult to compare the high and low performance of the process of different wafer manufacturers at the micro level.
4. CPU performance test: Extremely overclocked A77 vs. 2.84GHz X1
Let me talk about the Snapdragon 870. The CPU part is a 1+3+4 architecture with frequencies of 3.2GHz, 2.42Ghz, and 1.80GHz. The 1+3 core is the Coterx-A77 architecture, the L3 cache is 4MB, and the 4 small cores are Cortex-A55 architecture, 1.8GHz frequency.
The CPU of Snapdragon 888 is also a 1+3+4 octa-core design, upgraded with a new architecture layout, especially the first ARM’s first super-large core architecture Cortex-X1, which claims to be 20% higher in theoretical performance than A78. The main frequency of the X1 core is the traditional 2.84GHz, with 1MB secondary cache.
At the same time, Snapdragon 888 also has three performance-level cores with A78 architecture, both clocked at 2.40GHz, each with 512KB secondary cache, and four A55 architecture energy-efficient cores, both clocked at 1.80GHz, each with 128KB secondary cache . These cores share 4MB L3 cache, 3MB system cache, and the total cache capacity of the entire chip reaches 8MB.
In this comparison, in the CPU part, theoretically the most improved Snapdragon 888 compared to the Snapdragon 870 is the Cortex-X1 super core, which is said to be stronger than the A78, followed by the full upgrade of the three A77 cores to the A78. As for The four small cores are still completely unchanged ancestral A55.
According to the actual test results, the Snapdragon 870 equipped with the Redmi K40 can reach single-core 1003 and multi-core 3350, and the Redmi K40 Pro equipped with the Snapdragon 888 can reach single-core 1135 and multi-core 3701.
In this evaluation system, although the Snapdragon 870 has narrowed the gap with the Snapdragon 888 by virtue of its 3.2GHz extreme overclocking, the single-core test results of the Snapdragon 888 are still improved by about 13% compared with the Snapdragon 870, and the multi-core test results have improved. About 10%, the gain of the X1 super-large core is still quite large.
5. GPU performance test: [email protected] vs. [email protected]
In terms of GPU, let’s talk about the Snapdragon 870 first. The frequency of its Adreno 650 GPU graphics core is exactly the same as that of the Snapdragon 865 Plus. Both are improved on the basis of the Snapdragon 865 587MHz, that is, Adreno 650 [email protected] , compared to the Snapdragon. 865 graphics rendering speed is about 10% faster.
Compared Xiaolong 865 Adreno650 @ 587MHz and Xiaolong 870 Adreno650 @ 670MHz , Xiaolong 888 breath elevated to Adreno660 @ 840MHz , Qualcomm has claimed that the graphics rendering performance up to 35% may be mainly it is due to 43% overclocking, and more We don’t know the details of multiple parameters due to lack of public information.
In this evaluation system, according to the measured results of GFXbench , [email protected] has achieved remarkable results.
The Snapdragon 888 equipped in the Redmi K40 Pro maintained the lead in all test sub-items. Among them, the high-load scenes such as the Aztec ruins Vulcan 1080p/conventional off-screen were the most aggressive, with a gap of 36%. The improvement of other test items is at least about 20%.
It seems that Snapdragon 888, with Adreno660’s overclocking up to 840MHz, does have a large gain in graphics capabilities and a higher limit on performance. At the same time, the Snapdragon 870 carried by the Redmi K40 is not too far behind, and is in the first echelon of the Android camp with the former.
6. CPU energy consumption and energy efficiency test: Snapdragon 870 and Snapdragon 888 have the same goal
We use PrefDog and Geekbench to collect the CPU power consumption data of the mobile phone and calculate the CPU energy efficiency ratio. The specific method is as follows: The settings of the Redmi K40 and Redmi K40 Pro participating in the test are unified to the lowest brightness, the flight mode is turned on, and the same version of Geekbench is used.
First use Prefdog to test the power consumption, first turn off all backgrounds of the phone, with the lowest brightness, and only turn on WiFi, to test the no-load power consumption of the phone at this time. The specific method is to select the phone desktop as the test software, and leave the phone to stand without any operation. , Get a section of power consumption curve and average power consumption value, and record the value.
Then use Geekbench to run the scores separately, collect average power consumption data and subtract the no-load data during the running time to get the power consumption of the mobile phone processor. Combined with the test results, the frame rate, power consumption, and energy consumption ratio data calculated from this are finally obtained.
In order to feel the difference between the two more intuitively, our direct test results and energy efficiency ratio calculation results are summarized in the following table for reference.
It can be found, either single-core or multi-core CPU, Redmi K40 Pro are equipped with Xiaolong 888 can provide more robust than the Redmi K40 contained Xiaolong 870 performance, of course, the power consumption will also increase, but two The energy efficiency ratio performance of the two is not much different (single-core gap 10%, multi-core gap 1%).
Therefore, combined with our previous special test results on Snapdragon 888 VS Snapdragon 865, it can be basically determined that in the extreme test scenario of Geekbench, whether it is Snapdragon 870 or Snapdragon 888, their CPU peak performance is compared The improvement produced by Snapdragon 865 is not linear, and the increase in power consumption will exceed the increase in performance.
7. GPU energy consumption and energy efficiency test: Snapdragon 870 outperforms
We use PrefDog and GFXbench to collect the GPU power consumption data of the mobile phone and calculate the GPU energy efficiency ratio. The specific method is as follows: the settings of the two mobile phones participating in the test are unified to the lowest brightness, the flight mode is turned on, and the same version of GFXbench is used.
First use Prefdog to test the power consumption, the brightness is the lowest, only turn on WiFi and the necessary tools, and test the no-load power consumption of the mobile phone at this time. The specific method is to select the mobile phone desktop as the test software, and leave the mobile phone to stand without any operation. Power consumption curve and average power consumption value, and record the value.
Then use GFXBench to perform a single off-screen running score, collect average power consumption data and subtract the no-load data during the running time, to get the power consumption of the mobile phone processor. Due to the cumbersome details of the specific test process, we will directly summarize our test results in the following table for reference.
It can be seen more intuitively that while Snapdragon 888 provides more powerful GPU performance, the power consumption will also increase. The energy efficiency ratio of each test item will be reduced compared to the Snapdragon 870 equipped with Redmi K40 (approximately The difference of about 20%), the difference in energy efficiency ratio between the two is really not that big.
Combining our previous Hengping comments on Snapdragon 865 and Snapdragon 888, we can basically conclude that whether it is Snapdragon 870 or Snapdragon 888, the GPU peak performance improvement of the previous Snapdragon 865 is not linear.
Of course, the above-mentioned various tests are more for extreme full load conditions, and the energy consumption in daily use will not be so high at all.
8. A series of tests on body temperature, storage, and AnTuTu
The test was carried out in an environment with a room temperature of about 21°C. Specifically, the Antutu running test is carried out in a constant temperature indoor environment, and the highest temperature of the fuselage before and after the running is measured with a temperature measuring gun.
The highest temperature of the Redmi K40 body was 27.4°C before the running points, and it rose to 34.8°C after the running points.
The highest temperature of the Redmi K40 Pro body was 28.9°C before the run, and rose to 39.5°C after the run.
The entire Redmi K40 series is equipped with dual-channel UFS 3.1. According to actual measurement, compared with the previous UFS2.1, it has achieved higher write performance, which is at the mainstream level, and it is more convenient to handle a large amount of data throughput.
The Redmi K40’s AnTuTu running score surpassed most of the Snapdragon 865 models, and is basically second only to the Kirin 9000 and Snapdragon 888 models in the Android camp.
Redmi K40 Pro’s AnTuTu runs at the top level of the Android camp, which is comparable to 888 models such as Xiaomi Mi 11.
Nine, screen experience: 120Hz E4 AMOLED put effort
If you must select the most important “three pieces” of current smart phones, I am afraid that you cannot escape the processor platform, screen and image module. In fact, from the analysis of the components of flagship mobile phones such as iPhone and Samsung by some analysis institutions, it is found that these three items account for the bulk of the BOM material cost.
The Redmi K40 series naturally inevitably invests in three major items, except for the processor we just tested and analyzed and the image performance we will talk about next. As the first big item that comes into view after unpacking and booting up, this display After first getting started, it is impressive.
The entire Redmi K40 series use E4 AMOLED screen, 6.67-inch straight screen design, regardless of brightness, contrast, or color
Accuracy, color performance, etc. have reached the top level. Peak brightness is 1300nit, contrast, 00,000:1, JNCD=0.36, △E=0.35. It is worth mentioning that Redmi K40 Pro received the highest rating of A+ in the test conducted by the authoritative screen testing agency DisplayMate.
The screen refresh rate of the Redmi K40 series reaches 120Hz, which means that more pictures can be displayed at the same time, bringing smoother picture performance in scenes such as video playback, system operation, and games. At the same time, the K40 industry first released a 360Hz three-finger touch, even far higher than some well-known gaming mobile phones.
However, the quality of a mobile phone screen is not only determined by the above-mentioned parameters. When watching the screen, we often experience eye fatigue because the color temperature of the ambient light does not match the color temperature of the screen.
The Redmi K40 series supports 360° front and rear dual light perception. Through the integrated judgment of the front and rear light sources of the fuselage through the front and rear light sensors, the recognition accuracy of ambient light is improved, and it supports 8192 levels of brightness adjustment and automatically performs smooth brightness adjustment.
It is worth mentioning that the Redmi K40 series has a built-in dedicated ambient light sensor, which can detect ambient light color information through multiple internal light channels, and compensate the screen color temperature according to different ambient light, so that the display color temperature is more in line with the ambient color temperature and more comfortable. With 360° light perception, accurate brightness and color temperature adjustment can be achieved in different environments.
Here we use Mijia desk lamp 1s (2600K-5000K color temperature adjustment) to adjust the color temperature of the ambient light, and test the color temperature adjustment of Redmi K40. As shown below, the effect is quite obvious.
X. Image experience: The actual measurement of different main cameras can ignore the differences
The image part of the three phones of the Redmi K40 series only differs in the main camera. Other aspects are completely the same. Simply put, Redmi K40 uses IMX582, Redmi K40 Pro uses IMX686, Redmi K40 Pro+ uses Samsung HM2, all three are equipped with the same 8MP super wide-angle sub-camera and classic 5MP telephoto macro sub-camera.
Among them, the IMX582 carried by the Redmi K40 is actually not much different from the IMX586. The main specifications of the two are the same: both are 1/2″ sensors, support 48 million photos through Remosaic hardware, and also support four-in-one 1.6μm. Large pixels.
The main difference is that IMX582 supports video recording at 4K resolution at 30 frames, while IMX586 supports 4K resolution at 60 frames. Except for video recording, there is not much difference between the two, so it can be regarded as a fine-tuned version of IMX586.
We have seen the IMX686 on the Redmi K30. It can directly display a 64 million pixel screen with 9248×6944 pixels in hardware, and has a four-in-one 1.6-micron large pixel unit, and it is a 1/1.7-inch large photosensitive element. With outsole + high pixels, F1.89 aperture, 6P lens, it is an upgrade of Sony IMX586.
In other words, from the paper parameters alone, the main camera of the Redmi K40 Pro is indeed slightly stronger than that of the Redmi K40.
Let’s first look at a set of 1X to 2X sample comparisons. Redmi K40 and Redmi K40 Pro have different color adjustment tendencies, and the difference in specific imaging details is almost imperceptible.
Due to the use of the same specifications of the super wide-angle sub-camera, the super wide-angle image performance of the two is equivalent.
In the case of relatively sufficient light, in grand scenes, the main camera of Redmi K40 Pro has relatively obvious advantages in imaging details due to larger pixels, and there is a more intuitive difference between the two in terms of imaging color adjustment.
Shooting at night, with relatively sufficient artificial light sources, it is difficult to observe the gap between Redmi K40 and Redmi K40 Pro.
In a low light environment with relatively lack of artificial light sources, the difference between Redmi K40 and Redmi K40 Pro will be more obvious. The most intuitive thing is that the latter’s picture is relatively pure, and the proofs can still remain relatively high when the night mode is not turned on. With some brightness, the HDR effect in night scene mode is more natural and softer than Redmi K40.
On the whole, the image performance of Redmi K40 and Redmi K40 Pro is basically similar. If you don’t go into the purity of the main camera in low-light environments, you don’t have a preference for one of the color palettes, and you don’t care about the 4K missing in the main camera of Redmi K40. The 60-frame video recording capability can ignore the division of the image system.
11. Charging endurance test: It may be the fastest 33W fast charge at present
The Redmi K40 series is equipped with a 4520mAh battery as standard, and how the battery life achieved based on different processor platforms has become a highlight.
Below we carry out specific measurements.
The author uses the Bilibili client to play online barrage video, silent, 75% brightness. According to the monitored current information, it can be estimated that the online video battery life of Redmi K40 under test conditions can reach about 12 hours.
Under the same test conditions, based on the monitored current information, it can be estimated that the Redmi K40 Pro’s online video battery life can reach about 8.2 hours under the test conditions.
All Redmi K40 series come with a 33W charger. It takes 50 minutes to charge from 3% to 100%. It may be the fastest charging model I have seen so far with a charging power of about 30W.
12.Summary: The Redmi K40 priced at 1999CNY is really great value
As we said in the preface, the Redmi K40 series only has the difference in processor platform, main camera and other fundamentals, and the other parts are highly consistent, so here we mainly look at the differences.
Let’s talk about the performance part first. Thanks to Qualcomm’s active response to dislocation competition, the Redmi K40 series completely abandoned the “entry version” mid-range machine, and directly is the dual flagship combination of Snapdragon 870 and Snapdragon 888. Since the Snapdragon 870 itself is the “ultimate overclocking version” of the Snapdragon 865, the overall specifications and architecture are basically the same as those of the Snapdragon 865 Plus, except that the main frequency of the super core has reached 3.2GHz, so it is called a dual flagship “new and old combination” “.
In terms of CPU, the Geekbench test results show that the Snapdragon 888 single-core running score of the Redmi K40 Pro is about 13% higher than that of the Snapdragon 870 on the Redmi K40, and the multi-core test result is about 10% higher. Under our test conditions, the CPU energy efficiency performance of the two is not much different, with a single core gap of 10% and a multi-core gap of 1%.
In terms of GPU, the GFXbench test results show that compared with the Snapdragon 870, some high-load scenarios of the Snapdragon 888 can increase by 36%. The improvement of other test items is at least about 20%. Under our test conditions, the energy efficiency performance of Snapdragon 888 is about 20% behind that of Snapdragon 870.
Looking at the performance of CPU and GPU together, the Redmi K40 Pro equipped with Snapdragon 888 has a higher limit performance limit. The Redmi K40 with Snapdragon 870 has relatively restrained power consumption and energy efficiency performance. The two focus are on They are different, but they are undoubtedly at the top level of the Android camp.
In the image part, we did not get the Redmi K40 Pro+ equipped with Samsung HM2. From the performance of the Redmi K40 equipped with IMX582 and the Redmi K40 Pro equipped with IMX686, there is no difference between the advantages and disadvantages in most usage scenarios, but the K40 Pro The purity of the dark-light picture and the imaging details are better, and the specifications of the other sub-cameras are exactly the same, so there is no need to go into details.
In other respects, thanks to the upward climb of the Xiaomi brand, the Redmi K40 series has more room to play. It is in line with the big brother Xiaomi, and it has worked hard on the screen-equipped with a 120Hz E4 AMOLED screen, and even got the “A+” of DisplayMate. Evaluation, the matching automatic color temperature adjustment, etc. are also not missing, achieving a considerable upgrade.
In general, in the Redmi K40 series, the Redmi K40 has become a special “fragrance” existence, and the experience is very similar to that of the Redmi K40 Pro on the basis of a lower budget-looking at the overall situation, the biggest difference can be found It is only the 36% increase in graphics processing capacity of 888 vs. 870 in high-load scenarios.
For this series of models, our buying advice is: Redmi K40 is suitable for chasers with the ultimate price-performance ratio, and every penny is spent on the blade; Redmi K40 Pro is suitable for flagship enthusiasts who are keen on ultimate performance and must compare the parameters. ; Redmi K40 Pro+ is actually a large storage version of Redmi K40 Pro with Samsung HM2 as the main camera, suitable for users who care about cost performance and relatively ample budget.