Comparison Apple iMac 21.5" 2017 MMQA2 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.

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.

The result shown by the PC processor in the test (benchmark) Passmark CPU Mark.

Passmark CPU Mark is a comprehensive test that allows you to evaluate CPU performance in various modes and with a different number of processed threads. The results are displayed in points; the more points, the higher the overall performance of the processor. For comparison: as of 2020, in low-cost solutions, the results are measured in hundreds of points, in mid-range models they range from 800 – 900 to more than 6,000 points, and individual top-end chips are capable of showing 40,000 points or more.

The result shown by the PC processor in the test (benchmark) Geekbench 4.

Geekbench 4 is a comprehensive cross-platform test that allows, among other things, to determine the efficiency of the processor in various modes. At the same time, according to the developers, the verification modes are as close as possible to various real tasks that the processor has to solve. The result is indicated in points: the more points — the more powerful the CPU, while the difference in numbers corresponds to the actual difference in performance ("twice the result — twice the power").

Note that the benchmark in Geekbench 4 is the Intel Core i7-6600U processor with a clock frequency of 2.6 GHz. Its power is estimated at 4000 points, and the performance of other tested CPUs is already compared with it.

The result shown by the PC processor in the test (benchmark) Cinebench R15.

Cinebench is a test designed to test the capabilities of the processor and graphics card. The creator of this benchmark, Maxon, is also known as the developer of the Cinema 4D 3D editor; this determined the features of testing. So, in addition to purely mathematical tasks, when using Cinebench R15, the processor is loaded with processing high-quality three-dimensional graphics. Another interesting feature is the extensive support for multithreading — the test allows you to fully check the power of chips that process up to 256 threads at a time.

Traditionally, for CPU benchmarks, the test results are indicated in points (more precisely, points — PTS). The more points scored by the CPU, the higher its performance.

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.