Comparison Apple iMac 21.5" 2015 MK142 vs Apple iMac 21.5" 4K 2015 MK452

Resolution of the screen installed in the monoblock (see "Type").

The higher the resolution, the clearer and more detailed image the screen can produce, but the more expensive it is. In addition, high resolutions require corresponding powerful graphics, which further affects the price of the entire computer. The minimum indicator for modern monoblocks is actually 1366x768 — this resolution allows, in particular, to play HD 720p video in proper quality. However, nowadays, the more advanced format is most widely used — Full HD, providing a resolution of 1920x1080. And in high-end monoblocks with a large diagonal and powerful graphics, there are also more solid resolutions — Quad HD(2560x1440, 3440x1440), Ultra HD 4K(3840x2160, 4096x2304) and even 5K(5120x2880) standards.

The specific model of the processor installed in the PC, or rather, its index within its series (see "Processor"). The full model name consists of the series name and this index — for example, Intel Core i3 3220; knowing this name, you can find detailed information about the processor (characteristics, reviews, etc.) and determine how suitable it is for your purposes.

The number of cores in a complete PC processor.

The core is a part of the processor designed to process one stream of commands (and sometimes more, for such cases, see "Number of threads"). Accordingly, the presence of several cores allows the processor to work simultaneously with several such threads, which has a positive effect on performance. However note that a larger number of cores does not always mean higher computing power — a lot depends on how the interaction between command streams is organized, what special technologies are implemented in the processor, etc. So, only chips of the same purpose (desktop, mobile) and similar series (see "Processor") can be compared by the number of cores.

In general, single-core processors are practically not found in modern PCs. Mainly desktop chips of the initial and middle level are made dual-core. Four cores are found both in desktop CPUs of the middle and advanced class, and in mobile solutions. And six-core and eight-core processors are typical for high-performance desktop processors used in workstations and gaming systems.

Clock speed of the CPU installed in the PC.

In theory, higher clock speeds have a positive effect on performance because they allow the CPU to perform more operations per unit of time. However, this indicator is rather weakly related to real productivity. The fact is that the actual capabilities of the CPU strongly depend on a number of other factors - the overall architecture, cache size, number of cores, support for special instructions, etc. As a result, you can compare by this indicator only chips from the same or similar series (see “CPU”), and ideally, also from the same generation. And that's pretty approximate.

Processor clock speed when running in TurboBoost or TurboCore mode.

Turbo Boost technology is used in Intel processors, Turbo Core — AMD. The essence of this technology is the same both there and there: if some of the cores work under high load, and some are idle, then some tasks are transferred from more loaded cores to less loaded ones, which improves performance. This usually increases the clock frequency of the processor; this value is indicated in this paragraph. See above for more information on clock speed in general.

The main manufacturers of video cards nowadays are AMD, NVIDIA and Intel, and each has its own specifics. NVIDIA produces primarily discrete solutions; Among the most common are the GeForce MX1xx, GeForce MX3xx, GeForce GTX 10xx series (in particular GTX 1050, GTX 1050 Ti and GTX 1060), GeForce GTX 16xx, GeForce RTX 20xx, GeForce RTX 30xx( GeForce RTX 3060, GeForce RTX 3060 Ti, GeForce RTX 3070, GeForce RTX 3070 Ti, GeForce RTX 3080, GeForce RTX 3080 Ti, GeForce RTX 3090, GeForce RTX 3090 Ti), GeForce RTX 4060 , GeForce RTX 4060 Ti, GeForce RTX 4070, GeForce RTX 4070 SUPER, GeForce RTX 4070 Ti, GeForce RTX 4070 Ti SUPER, Ge Force RTX 4080, GeForce RTX 4080 SUPER, GeForce RTX 4090 and separate Quadro series. AMD offers both discrete and integrated graphics - including the popular Radeon RX 500, Radeon RX 5000, Radeon RX 6000, Radeon RX 7000 and AMD Radeon Pro series. And Intel deals exclusively with modules integrated into processors of its own production - these can be HD Graphics, UHD Graphics and Iris.

Note that many configurations with discrete graphics also have an integrated graphics module; in such cases, the name of the discrete video card is indicated as more advanced.

In most desktop PCs, this assortment is determined both by connectors on the "motherboard" and on a discrete graphics card, among which VGA, DVI, HDMI output(there are models where HDMI 2 pcs), HDMI input, DisplayPort, miniDisplayPort. More details about them.

— VGA. He's D-Sub. Analogue video output with maximum resolution up to 1280x1024 and no audio support. It is rarely installed in modern devices, but it can be useful for connecting certain models of projectors and TVs, as well as outdated video equipment.

— DVI. Modern PCs can be equipped with both pure digital DVI-D and hybrid DVI-I; the latter also allows analogue connection, including work with VGA-devices through an adapter, and in analogue format has a resolution of 1280x1024. In digital DVI, this parameter can reach 1920x1200 in single-link mode (single link) and 2560x1600 in dual-link mode. The presence of a dual-channel mode must be specified separately.

— HDMI output. Digital output originally designed for HD content — high-definition video and multi-channel audio. The HDMI interface is almost mandatory for modern HD multimedia technology, and it is also extremely popular in computer monitors — so the presence of such an output on a PC provides ve...ry extensive features for connecting external screens and even high-end audio devices. Some devices may even have 2 HDMI outputs.

— HDMI input. Your PC has at least one HDMI input. See above for details on the interface itself; here we note that it is the inputs of this format that are found mainly in monoblocks (see "Type"). At a minimum, this allows you to use the monoblock's own display as a screen for another device (for example, as an external monitor for a laptop). However, there are other, more specific options for using the HDMI input — for example, recording an incoming video signal, or transferring (switching) it to one of the PC video outputs.
Both the HDMI inputs and outputs in modern PCs may correspond to different versions:

• v 1.4. The earliest standard widely used today. Supports resolutions up to 4096x2160 and frame rates up to 120 fps (however, only at a resolution of 1920x1080 or lower), and can also be used to transmit 3D video. In addition to the original version 1.4, you can find improved v 1.4a and v 1.4b — in both cases, the improvements affected mainly the work with 3D.
• v2.0. The standard, also known as HDMI UHD, was the first to introduce full support for UltraHD 4K, with frame rates up to 60 fps, as well as compatibility with a 21:9 aspect ratio. In addition, the number of simultaneously transmitted channels and audio streams has increased to 32 and 4, respectively. It is also worth noting that initially version 2.0 did not provide support for HDR, but it appeared in update v 2.0a; if this feature is important to you, it's ok to clarify which version 2.0 is provided in the PC, the original or the updated one.
• v2.0b. The second update of the above v 2.0. The main update was the expansion of HDR capabilities, in particular, support for two new formats.
• v2.1. It is also HDMI Ultra High Speed: the bandwidth has been increased to such an extent that it became possible to transfer 10K video at 120 fps (not to mention more modest resolutions) as well as work with extended colour schemes up to 16 bits. The latter may come in handy for some professional tasks. However, note that all the features of HDMI v 2.1 are available only when using cables designed for this standard.

— Display port. A digital media interface similar in many respects to HDMI, but mainly used in computer technology — in particular, it is widely used in Apple computers and monitors. One of the interesting features of this standard is the ability to work in the daisy chain format — connecting several screens to one port in series, transmitting its own signal to each of them (although this function is not technically available with all screens for this interface). DisplayPort is also on the market in several versions, the current ones are as follows:

• v 1.2. The earliest widely used version (2010). However, already in this version, 3D compatibility and the daisy chain mode appeared. The maximum fully supported resolution when connecting a single monitor is 5K (30 fps), transmission up to 8K is possible with certain restrictions; a frame rate of 60 Hz is supported up to a resolution of 3840x2160, and 120 Hz — up to 2560x1600. And when using daisy chain, you can connect up to 2 2560x1600 screens at 60 frames per second or up to 4 1920x1200 screens at the same time. In addition to the original version 1.2, there is an improved v 1.2a, the main innovation of which is support for AMD FreeSync, a technology for synchronizing the monitor's frame rate with the signal from an AMD graphics card.
• v 1.3. An update introduced in 2014. The increased bandwidth made it possible to provide full, without restrictions, support for 8K at 30 fps, as well as transmit 4K images at 120 fps, sufficient for 3D work. Resolutions in daisy chain mode have also increased — up to 4K (3840x2160) at 60 fps for two screens and 2560x1600 at the same frame rate for four. Of the specific innovations, it is worth mentioning the Dual Mode mode, which allows you to connect HDMI and DVI devices to such a connector through the simplest passive adapters.
• v 1.4. The newest version widely used in modern PCs. Formally, the maximum connection speed has not increased compared to the previous version, but thanks to signal optimization, it became possible to work with 4K and 5K resolutions at 240 fps and with 8K at 120 fps. However for this, the connected screen must support DSC encoding technology — otherwise, the available resolutions will not differ from version 1.3. In addition, v 1.4 added support for a number of special features, including HDR10, and the maximum number of simultaneously transmitted audio channels increased to 32.

— miniDisplayPort. A smaller version of the DisplayPort connector described above, may also correspond to different versions (see above). Note that the same hardware connector is used in the Thunderbolt interface versions 1 and 2, and the graphic part of this interface is based on DisplayPort. Therefore, even some Thunderbolt monitors can be directly connected to miniDisplayPort (although it is desirable to clarify this possibility separately).

— COM port (RS-232). Serial port, originally used to connect dial-up modems and some peripherals, in particular, mice. However, today this interface is used as a service interface in various devices — TVs, projectors, network equipment (routers and switches), etc. Connecting to a PC via RS-232 allows you to control the operation parameters of an external device from a computer.

The presence of a mini-Jack connector (3.5 mm) on the front panel of the PC. More precisely, in ordinary desktop PCs, gaming systems and monoblocks (see "Type") there are most often two such connectors: one plays the role of an output for headphones, speakers, etc., the second plays the role of a microphone input. But in compact devices like some mini-Jack nettops, there can be only one — a universal port, in which you can turn on both headphones / speakers and a headset with one common plug for a microphone and “ears”.

Anyway, such connectors are closer to the user and are more convenient to connect than similar sound card outputs on the rear panel of the case.

The presence of a keyboard and mouse included with the PC. This configuration eliminates the need to purchase these accessories separately, and the bundled peripherals, by definition, will be optimally compatible with the computer. On the other hand, it is worth considering that the kit usually includes fairly simple keyboards and mice; For a demanding user - for example, an enthusiastic gamer - such equipment may not be advanced enough. Also, input Devices may differ in connection method.

- Wired. Wired keyboards and mice are inexpensive and do not require their own power sources - that is, they provide unlimited operation time, without the need to change batteries or charge the battery. In addition, they are suitable for even the most inexpensive PCs that are not equipped with Bluetooth or Wi-Fi wireless modules. The disadvantages of this option include: firstly, the actual presence of a wire, which limits mobility and which sometimes has to be pulled through hard-to-reach places; secondly, the need to have free ports for connection. At the same time, these shortcomings are not so often critical, so most modern PCs with input Devices are supplied with wired accessories.

- Wireless. Wireless keyboards and mice provide the user with additional convenience: they allow you to move freely within a radius of at least a few meters from the computer, without worrying about how to place the wire the next time you move. On the...other hand, such input Devices are noticeably more expensive than wired ones; their operation requires a power source - batteries or an accumulator, and the operating time from such a source is limited (although it is often measured in weeks or even months). In addition, to use wireless peripherals, the corresponding connection interface (most often Bluetooth) must be supported by the computer itself, which is not the case in every configuration. Therefore, wireless accessories are included in the package much less frequently than wired ones.