Comparison ASRock B250M Pro4 vs ASRock B250 Pro4

The form factor of the motherboard determines, first of all, its physical dimensions, and, accordingly, a number of parameters directly related to them: type of computer case, installation method, type of power connector, number of slots for additional boards (expansion slots), etc. At the moment, there are such main form factors of motherboards:

— ATX. One of the most common form factors for PC motherboards. The standard size of such a board is 30.5x24.4 cm, it has up to 7 expansion slots and a 24-pin or (less often, in older models) 20-pin power connector.

— Micro-ATX. A slightly reduced version of the ATX form factor, with more compact dimensions (usually 24.4x24.4 cm) and, accordingly, fewer places for peripherals — there are usually only two slots for "RAM", expansion slots — from two to four. Nevertheless, despite the limited size, such boards can be intended for quite powerful systems.

— Mini-ITX. Motherboards of compact dimensions (17x17 cm). Designed for use primarily in small form factor computers (small form factor, SFF), in other words, compact PCs. According to the mounting specifications and the location of connectors and slots, they are compatible with ATX standard cases. They usually have one expansion slot.

— mini-STX. Another representative of compact form factors, assuming a boar...d size of 140x147 mm. Thus, the overall size is almost a third smaller than mini-ITX. At the same time, such motherboards often have seats for fairly powerful processors (for example, the LGA 1151 socket for Intel Core chips) and are made based on the corresponding TDP values. But expansion slots, usually, are absent.

— micro DTX. A relatively new compact form factor, which is not common, mainly among rather specific motherboards — in particular, models designed for cases in the PIO form factor. This form factor is characterized by a very small size and weight and allows you to mount the case directly behind the monitor, on a standard VESA mount. One of the features of "motherboards" for such systems is that the graphics card is installed along the board, and not perpendicularly — accordingly, the PCI-E 16x connector (see below) has a non-standard location. At the same time, micro-DTX boards are similar in terms of fasteners to microATX and can be used in cases of the corresponding form factor (except that additional equipment may be required for the correct installation of a graphics card). The standard size of such a board is 170 x 170 mm, similar to mini-ITX.

— mini DTX. An intermediate format between the microDTX described above and the original DTX; sometimes also described as an extended mini-ITX version. It has a standard size of 170 x 203 mm and can be equipped with two expansion slots (mini-ITX and mini-DTX have one such slot); it is completely similar in application — it is intended mainly for compact cases, in particular, HTPC computers.

— XL-ATX. Larger version of the ATX form factor. While not yet a common standard, size options include 32.5x24.4cm with 8 expansion slots and 34.3x26.2cm with up to 9 expansion slots.

— Thin mini-ITX. A “thin” version of the reduced mini-ITX form factor described above: according to the official specification, the total thickness of the thin mini-ITX board should not exceed 25 mm. Also designed for the most miniature computers — in particular, HTPC.

— E-ATX. The letter E in the name of this form factor stands for "Extended" — extended. True to its name, E-ATX is another enlarged version of ATX using 30.5x33cm boards.

— EEB. Full name SSI EEB. The form factor used in server systems (see “By direction”) provides a board size of 30.5x33 cm.

— CEB. The full name is SSI CEB. Another form factor of "server" motherboards. In fact, it is a narrower version of the EEB described above, with a width reduced to 25.9 cm (with the same height of 30.5 cm).

— flex-ATX. One of the compact variations of ATX, which provides board dimensions of less than 229x191 mm, as well as less than 3 expansion slots. At the same time, in terms of the location of the mounting holes, this standard is identical to microATX; in fact, it was developed as a potential replacement for the latter, but for a number of reasons it did not receive much distribution, although it continues to be produced.

— Non-standard (Custom). The name Proprietary is also used. Motherboards that do not conform to standard form factors and are designed for cases of special sizes (usually branded ones).

The number of processor power phases provided on the motherboard.

Very simplistically, phases can be described as electronic blocks of a special design, through which power is supplied to the processor. The task of such blocks is to optimize this power, in particular, to minimize power surges when the load on the processor changes. In general, the more phases, the lower the load on each of them, the more stable the power supply and the more durable the electronics of the board. And the more powerful the CPU and the more cores it has, the more phases it needs; this number increases even more if the processor is planned to be overclocked. For example, for a conventional quad-core chip, only four phases are often enough, and for an overclocked one, at least eight may be needed. It is because of this that powerful processors can have problems when used on inexpensive low-phase motherboards.

Detailed recommendations on choosing the number of phases for specific CPU series and models can be found in special sources (including the documentation for CPU itself). Here we note that with numerous phases on the motherboard (more than 8), some of them can be virtual. To do this, real electronic blocks are supplemented with doublers or even triplers, which, formally, increases the number of phases: for example, 12 claimed phases can represent 6 physical blocks with doublers. However, virtual phases are much inferior to real ones in terms of capabilities — in fact, t...hey are just additions that slightly improve the characteristics of real phases. So, let's say, in our example, it is more correct to speak not about twelve, but only about six (though improved) phases. These nuances must be specified when choosing a motherboard.

Motherboard dimensions in height and width. It is assumed that the traditional placement of motherboards is vertical, so in this case one of the dimensions is called not the length, but the height.

Motherboard sizes are largely determined by their form factors (see above), however, the size of a particular motherboard may differ slightly from the standard adopted for this form factor. In addition, it is usually easier to clarify the dimensions according to the characteristics of a particular motherboard than to look for or remember general information on the form factor. Therefore, size data can be given even for models that fully comply with the standard.

The third dimension — thickness — is considered less important for a number of reasons, so it is often omitted.

The number of M.2 connectors provided in the design of the motherboard. There are motherboards for 1 M.2 connector, for 2 connectors, for 3 connectors or more.

The M.2 connector is designed to connect advanced internal devices in a miniature form factor — in particular, high-speed SSD drives, as well as expansion cards like Wi-Fi and Bluetooth modules. However, connectors designed to connect only peripherals (Key E) are not included in this number. Nowadays, this is one of the most modern and advanced ways to connect components. But note that different interfaces can be implemented through this connector — SATA or PCI-E, and not necessarily both at once. See "M.2 interface" for details; here we note that SATA has a low speed and is used mainly for low-cost drives, while PCI-E is used for advanced solid-state modules and is also suitable for other types of internal peripherals.

Accordingly, the number of M.2 is the number of components of this format that can be simultaneously connected to the motherboard. At the same time, many modern boards, especially mid-range and top-end ones, are equipped with two or more M.2 connectors, and moreover, with PCI-E support.

Electrical (logical) interfaces implemented through physical M.2 connectors on the motherboard.

See above for more details on such connectors. Here we note that they can work with two types of interfaces:

• SATA is a standard originally created for hard drives. M.2 usually supports the newest version, SATA 3; however, even it is noticeably inferior to PCI-E in terms of speed (600 MB / s) and functionality (only drives);
• PCI-E is the most common modern interface for connecting internal peripherals (otherwise NVMe). Suitable for both expansion cards (such as wireless adapters) and drives, while PCI-E speeds allow you to fully realize the potential of modern SSDs. The maximum communication speed depends on the version of this interface and on the number of lines. In modern M.2 connectors, you can find PCI-E versions 3.0 and 4.0, with speeds of about 1 GB / s and 2 GB / s per lane, respectively; and the number of lanes can be 1, 2 or 4 (PCI-E 1x, 2x and 4x respectively)

Specifically, the M.2 interface in the characteristics of motherboards is indicated by the number of connectors themselves and by the type of interfaces provided for in each of them. For example, the entry "3xSATA / PCI-E 4x" means three connectors that can work both in SATA format and in PCI-E 4x format; and the designation "1xSATA / PCI-E 4x, 1xPCI-E 2x" means two connectors, one of which works as SATA or PCI-E 4x, and the second — only as PCI-E 2x.

Number of PCI-E (PCI-Express) 1x slots installed on the motherboard. There are motherboards for 1 PCI-E 1x slot, 2 PCI-E 1x slots, 3 PCI-E 1x ports and even more.

The PCI Express bus is used to connect various expansion cards — network and sound cards, video adapters, TV tuners and even SSD drives. The number in the name indicates the number of PCI-E lines (data transfer channels) supported by this slot; the more lines, the higher the throughput. Accordingly, PCI-E 1x is the basic, slowest version of this interface. The data transfer rate for such slots depends on the PCI-E version (see "PCI Express Support"): in particular, it is slightly less than 1 GB / s for version 3.0 and slightly less than 2 GB / s for 4.0.

Separately, we note that the general rule for PCI-E is as follows: the board must be connected to a slot with the same or more lines. Thus, only single-lane boards will be guaranteed to be compatible with PCI-E 1x.

The number of USB 2.0 connectors installed on the back of the motherboard.

Recall that USB is the most popular modern connector for connecting various external peripherals — from keyboards and mice to specialized equipment. And USB 2.0 is the oldest version of this interface that is relevant today; it is noticeably inferior to the newer USB 3.2 both in terms of speed (up to 480 Mbps), and in terms of power supply and additional functionality. On the other hand, even such characteristics are often enough for undemanding peripherals (like the same keyboards / mice); and devices of newer versions can be connected to the connectors of this standard — there would be enough power supply. So this version of USB is still found in modern motherboards, although there are fewer and fewer new models with USB 2.0 connectors.

Note that in addition to the connectors on the rear panel, connectors on the board itself (more precisely, ports on the PC case connected to such connectors) can also provide a USB connection. See below for more on this.

The number of PS/2 ports provided in the design of the motherboard.

PS/2 is a dedicated port designed to connect exclusively to keyboards and/or mice. The traditional motherboard configuration for a PC provides 2 such ports — for the keyboard (usually highlighted in lilac) and for the mouse (green). However, there are boards with one connector, to which you can connect any of these types of peripherals, to choose from. Anyway, the presence of PS/2 can save the user from having to occupy USB ports for the keyboard / mouse; this is especially useful if you have to deal with a lot of other USB peripherals. On the other hand, for a number of reasons, this connector is considered obsolete and is used less and less; and PS/2 peripherals are produced mainly in the form of USB devices, additionally equipped with PS/2 adapters.