Comparison Apple iMac 27" 5K 2017 MNE92 vs Apple iMac 21.5" 4K 2015 Z0RS00013

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

In general, the larger the diagonal, the more advanced both the screen and the computer as a whole are considered. The large display size is convenient for games, movies, and some special tasks like layout of large printed materials; in addition, a higher resolution can be provided for such a screen, and more space is available inside the case for advanced components. On the other hand, a larger monoblock will cost much more than a relatively small one, even if the other characteristics of such models are completely the same. In addition, the power of the hardware is not directly related to the size of the screen — high-end monoblocks can be quite small.

As for specific numbers, a diagonal of 20" or less is considered very limited nowadays, monoblocks of 21.5" are small, a 24" screen is medium, and values of 27" and 32" indicate large sizes.

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 maximum brightness provided by the monoblock screen (see "Type").

The more intense the ambient light, the higher the screen brightness should be for normal visibility. The most "dim" screens in monoblocks are capable of delivering up to 200 cd / m2 — this is more than enough to work under ordinary artificial lighting, but under sunlight it will take at least 300 cd / m2. At the same time, modern monoblocks can also have a larger margin of brightness — in some models up to 500 cd / m2. This expands the possibilities for customizing the screen for different situations and user preferences. In addition, high brightness has a positive effect on image quality and colour saturation, in light of which it is often a sign of a fairly advanced screen.

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 threads supported by the bundled PC processor.

A thread in this case is a sequence of instructions executed by the kernel. Initially, each individual core is able to work with only one such sequence. However, among modern CPUs, more and more often there are models in which the number of threads is twice the number of cores. This means that the processor uses multi-threading technology, and each core works with two instruction sequences: when pauses occur in one thread, the core switches to another, and vice versa. This allows you to significantly increase performance without increasing the clock frequency and heat dissipation, however, such CPUs are also more expensive than single-threaded counterparts.

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 amount of cache memory level 3 (L3) in the complete PC processor.

The cache is an intermediate memory buffer into which, when the processor is running, the most frequently used data from the "RAM" is written. This has a positive effect on system performance. The larger the cache, the more data can be stored in it for quick access and the higher the performance (ceteris paribus). As for the level, the higher it is, the larger and slower the cache. The third cache level is the highest, respectively, the most voluminous and the slowest. Its minimum volume in modern PCs is about 2 MB, and the most advanced processors can have 20 – 30 MB of L3 cache.

The type of RAM used in the computer. This indicator describes both the general level of "RAM" and the possibilities for replacing and upgrading it: different types of RAM are not compatible with each other.

Here are the types of memory that are relevant for modern PCs:

— DDR3. The third generation of RAM with the so-called double data transfer. Some time ago, this standard was the most popular in computer technology, but now it is increasingly losing ground to newer and more advanced standards, primarily DDR4. In compact computers, there is a "mobile", energy-saving version of this memory standard — LPDDR3.

— DDR3L. A modification of DDR3 memory that supports operation at a reduced voltage — 1.35 V instead of 1.5 V (Low Voltage — hence the index L). Lower voltage improves performance. These modules are compatible with classic DDR3 slots.

— DDR4. Further, after DDR3, the development of the DDR standard, released in 2014. It features both increased performance and increased volumes — the capacity of one bar can be from 2 to 128 GB. Thus, the maximum amount of RAM in most PCs is limited more by the capabilities of the motherboard than by the characteristics of existing brackets. DDR4 is very popular in modern computer technology, including desktop PCs.