Comparison Oukitel WP21 Ultra 256 GB / 12 GB vs Oukitel WP21 256 GB / 12 GB

The maximum brightness in nits provided by the smartphone display.

The brighter the display, the more readable the picture remains on it under intense ambient light (for example, outdoors on a clear sunny day). Also, high brightness is important for the correct displaying of HDR content. However, a large amount of brightness affects the cost and power consumption of the screen. Manufacturers can specify standard, maximum, and peak brightness values. At the same time, an equal sign cannot be put between the maximum and peak brightness. The first indicates the ability of the screen to produce the specified brightness over its entire area, while the peak one — in a limited area and for a short time (mainly for HDR content).

Second display, in addition to the main one. Features of such a display depend on a number of specs of the device itself. For example, in clamshell phones, an additional screen allows you to receive notifications about received messages, incoming calls, etc., without opening the phone once again and without wearing out the rotary mechanism. And in modern smartphones, the second display can be "electronic paper"; it is used for simple tasks like reading books or mail, though it can significantly save battery power. At the same time, clamshell phones are practically out of use today, and installing a second screen in a smartphone significantly complicates the design and increases its cost. Therefore, this feature is not very popular.

"clean" Android operating system/

The Android OS is open source, allowing developers to create various modifications of this OS, including branded builds and software shells. Such modifications can be quite advanced, but they often change or even limit the functionality of the original Android, and updates to such firmware are highly dependent on their creators and often fall back behind updates to the original OS. Thus, some users prefer to use "clean", stock Android, without any add-ons or shells; those devices are designed for them.

The clock frequency of the CPU that the device is equipped with. For multi-core processors, which are standard in modern smartphones, the frequency of each individual core is implied; and if the processor has cores with different frequencies (see "Number of cores") — usually, the maximum indicator is given.

In general, high performance smartphones have high frequency of the processor. However, note that this parameter itself is not directly related to the capabilities of the CPU: many other features of the chip affect the actual performance, and often a low cost solution with a higher clock speed turns out to be less performant than an expensive one, and at the same time, presumably, more "slow" processor. In addition, the overall performance of the system directly depends on a whole set of other factors — primarily the amount of RAM. Therefore, when evaluating a smartphone, it is worth focus not so much on the frequency of the processor, but on the general specs of the system and visual indicators like the results in tests (see below).

The type of RAM installed in the smartphone.

All modern devices use LPDDR format RAM ( LPDDR4, LPDDR4x, LPDDR5, LPDDR5x, LPDDR5T). In addition to its miniature size, it differs from conventional computer RAM in supporting special data transfer formats (16- and 32-bit memory buses). But versions of such memory can be different:

- LPDDR3. The earliest current generation of LPDDR was introduced in 2012 and has been implemented in devices since 2013. Standardly operates at speeds up to 1600 MT/s (megatransactions per second) and frequencies up to 933 MHz; The “improved” version supports speeds up to 2133 MT/s. Nowadays, this standard is rarely found, mainly among outdated mobile devices.

- LPDDR4. The successor to LPDDR3, officially introduced in August 2014 (although the first hardware developments were released at the end of 2013). The operating speed, compared to its predecessor, has doubled - up to 3200 MT/s; frequency increased to 1600 MHz; and energy consumption was reduced by 40%. In addition, the data transfer format has changed - in particular, instead of one 32-bit bus, two 16-bit buses are used, and some security improvements have been introduced into the standard. This memory can be found in some medium-range smartphones. - LPDDR4x. An improved version of LPDDR4 wit...h reduced power consumption - the standard uses a voltage of 0.6 V instead of 1.1 V. In addition, some improvements were implemented in this type of RAM aimed at increasing speed (it reaches 4266 MT/s) and general optimization of operation - for example, a single-channel mode for undemanding applications. Thanks to such characteristics, this version of memory has become noticeably more widespread than the original LPDDR4. You can find it in mid- and high-end devices.

- LPDDR5. Further development of “mobile” RAM, officially announced at the beginning of 2019. The operating speed in this version is increased to 6400 MT/s, a differential signal format was introduced to improve resistance to interference and errors, and dynamic frequency and voltage control was introduced to reduce power consumption. The use of such memory modules is typical mainly for high-end smartphones.

- LPDDR5x. A more energy efficient and faster version of LPDDR5 RAM. The data transfer speed in it was increased to 8533 MT/s, and the peak throughput indicator was increased to 8.5 Gbit/s. The number of memory banks per channel in LPDDR5x is always 16. RAM of this standard is typical for advanced smartphones of the highest grade.

- LPDDR5T. T is for turbo. The operating speed of the LPDDR5T standard RAM has been increased to 9600 MT/s, and devices with such memory modules are about 13% faster compared to LPDDR5X. The memory operates in the low voltage range from 1.01 to 1.12 V. The corresponding modules are aimed at use in high-end mobile devices.

The type of the phone's storage.

The specification determines, first of all, the speed of the memory, and, accordingly, the performance of the device as a whole (especially when working with large amounts of data or resource-intensive applications). Nowadays, there are two basic specifications — eMMC and UFS; each of them has several versions. In general, storages with UFS 3.1 and UFS 4.0 are the fastest and most advanced today, but they cost accordingly, and therefore are used mainly in premium smartphones. A more detailed description of these standards looks like this:

— eMMC. One of the simplest and most affordable standards for solid state memory — for example, this specification is used by most flash drives. In smartphones and other portable gadgets, this standard was generally accepted until 2016, when the introduction of UFS began; however, even now it is very popular — mainly due to its low cost and low power consumption. But the speeds of eMMC are noticeably lower than those of UFS. So, in the latest version of eMMC 5.1A (2019), the read speed is up to 400 MB/s, and the earlier and more common version of eMMC 5.1 provides up to 250 MB/s in read mode, up to 125 MB/s in sequential write mode and all only up to 7.16 MB/s with random writes (in other words, in application mode).

— UFS. A solid state drive standard designed to be a faster, more advanced successor to eMM...C. In addition to the increased data exchange speeds, the format of work has also been changed in UFS — it is fully duplex, that is, reading and writing can be performed simultaneously (whereas in eMMC these processes were performed in turn). Also, efficiency in random read and write mode has been significantly improved, which has a positive effect on the quality of work with applications. Specific data exchange rates and features of work depend on the version of UFS, nowadays you can find the following options:

• 2.0. The earliest of the versions found in modern smartphones; was released back in 2013. Provides data transfer rates up to 1.2 GB/s, the maximum available in this version. The newer version 2.1 has the same speeds, but it is supplemented with a number of important innovations. Therefore, UFS 2.0 memory is rarely used in mobile phones.
• 2.1. The first of the versions that are widely used in smartphones; was released in 2016. In terms of speed, it does not differ from version 2.0 described above, and the main differences are in some improvements. In particular, UFS 2.1 introduced storage status indicator (“health”), the ability to remotely update the firmware, as well as a number of solutions aimed at improving overall reliability.
• 2.2. An evolution of the UFS 2.x standard introduced in Summer 2020. A key improvement is the introduction of the WriteBooster feature (originally introduced in UFS 3.1); this feature allows you to significantly increase the write speed and, accordingly, the overall performance in tasks like running applications.
• 3.0. A version released in 2018 and implemented in hardware a year later. The throughput was increased to 2.9 GB/s per two lines (1.45 GB/s per one), new versions of the M-PHY electronic protocol (physical layer) and UniPro based on it were introduced, the reliability of working with data and the temperature mode of operation of the controllers has been expanded (theoretically, it can range from -40 °С to 105 °С). UFS 3.0 is used mainly in fairly advanced smartphones, although in the future we can expect this specification to be extended to more modest models.
• 3.1. The successor to the UFS 3.0 standard, officially introduced in early 2020. It is positioned as a specification created specifically for high-performance mobile devices and aimed at increasing speed while minimizing power consumption. To do this, UFS 3.1 has a number of innovations: a non-volatile Write Booster cache to speed up writing; special DeepSleep power saving mode for relatively simple and inexpensive systems; as well as the Performance Throttling Notification feature, which allows the drive to send overheating signals to the control system. In addition, this standard may additionally provide support for the HPB extension, which improves reading speed.
• 4.0. UFS 4.0 doubled the throughput per lane (23.2 Gbps per lane) and improved energy efficiency by about 46% (compared to the previous 3.1 specification). UFS 4.0 standard memory modules provide maximum read speed up to 4200 MB/s, write speed up to 2800 MB/s. The high bandwidth makes the memory standard ideal for 5G smartphones.

The largest volume of memory card with which the phone supports. For more information about the cards themselves, see "Memory Card Slot"; here we note that capacious cards often use advanced technologies that are not supported by all devices, and sometimes phones simply do not have enough power to process large amounts of data. Therefore, for the convenience of choosing in our catalog, the maximum supported volume is indicated.

In fact, there are cases when some devices may exceed the claimed characteristics. However, it is worth focusing on official data, because, if officially supported volume is exceeded, normal operation of the card is not guaranteed.

The quantity and types of removable cards (SIM, memory cards) that can be installed in the phone. On E-Catalog this parameter is specified only for devices that allow the installation of more than one SIM card — most often that means 2 SIM cards, however, you can find devices with three or even four corresponding slots.

Initially several slots mean that several phone numbers can be used on one device. Thus it is possible to combine personal and work numbers, separate plans for calls and the Internet, etc. in one device. However modern devices (especially smartphones) often provide the combined design “SIM + SIM / memory card " : one of the slots is intended only for SIM, the second can be used both for a SIM card or for a memory card such as microSD or Nano Memory (see "Memory card slot"). At the same time, there is no separate slot for a memory card in the device, so the user has to choose between the second number and additional storage. Therefore, if you want to use 2 SIM cards and a memory card at the same time, you should pay attention to models where this is directly stated.

It is also worth considering that individual slots may differ in the type of compatible SIM cards; see below for details.

The test results are specified either by a younger model in a line or a particular model, made for a better understanding performance of phone models if you compare phones against these parameters. For example, the 128 GB model has test results, and the 256 GB model has no information on the network, and in both models you will see the same value that will give an understanding of the overall performance of the device. But if the editorial office has information for each model individually, then each model will have its test results filled out, and the model with bigger RAM will have bigger values.