Form factor
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:
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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.
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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.
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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.
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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).Power phases
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.
Size (HxW)
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.
1x PCI-E slots
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.
RGB LED strip
Connector for connecting a decorative LED strip and other devices with LED indication. Allows you to control the backlight of the case through the motherboard and customize the glow for your tasks, including synchronize it with other components.
USB 3.2 gen2
The number of native USB 3.2 gen2 connectors provided on the back of the motherboard. In this case, we mean traditional, full-size USB A ports.
USB 3.2 gen2(formerly known as USB 3.1 gen2 and simply USB 3.1) is the evolution of USB 3.2 after version 3.2 gen1 (see above). This standard provides connection speeds up to 10 Gbps, and to power external devices in such connectors, USB Power Delivery technology (see below) can be provided, which allows you to output up to 100 W per device (however, Power Delivery support is not mandatory, its presence should be specified separately). Traditionally for the USB standard, this interface is backwards compatible with previous versions — in other words, you can easily connect a device supporting USB 2.0 or 3.2 gen1 to this port (unless the speed will be limited by the capabilities of a slower version).
The more connectors provided in the design, the more peripheral devices can be connected to the motherboard without the use of additional equipment (USB splitters). In some models of motherboards, the number of ports of this type is
5 or even more. At the same time, we note that in addition to the connectors on the rear panel, connectors on the board itself (more precisely, ports on the case connected to such connectors) can also provide a USB connection. See below for more on this.
USB C 3.2 gen1
The number of
USB-C version 3.2 gen1 connectors provided on the back of the motherboard.
USB-C is a relatively new type of connector used in both portable and desktop PCs. It has a small size and a convenient double-sided design, thanks to which the plug can be inserted into the connector in either direction. And version 3.2 gen1 connectivity (formerly known as USB 3.1 gen1 and USB 3.0) allows you to work at speeds up to 4.8 Gbps. In addition, when using this version with a USB-C connector, this port can implement USB Power Delivery technology, which allows you to supply power up to 100 W to external devices (although not every USB-C 3.2 gen1 port on motherboards supports Power Delivery).
As for the quantity, modern motherboards almost never have more than one USB-C 3.2 gen1 connector. This is related to two things. Firstly, not many peripherals with a USB-C plug are available for desktop PCs — full-sized USB A are still more popular; secondly, many manufacturers prefer USB-C ports of more advanced versions — 3.2 gen2 and 3.2 gen2x2 (see below). Also note that in addition to the connectors on the rear panel, connectors on the board itself (more precisely, ports on the case connected to such connectors) can also provide a USB connection. See below for more on this.
Fan power connectors
The number of connectors for powering coolers and fans provided in the motherboard. A processor cooler is usually connected to such a connector, and fans of other system components — video cards, cases, etc. can also be powered from the "motherboard"; sometimes it is more convenient than pulling power directly from the PSU (at least you can reduce the number of wires in the case). Many modern boards are equipped with
4 or more connectors of this type.
CPU Fan 4-pin
A four-pin connector used to connect a processor cooling fan. The first contact in it corresponds to the black wire of the cooler — it is the "ground" or minus of the power supply. The second contact is the plus of the power supply (yellow or red cooler wire). The third one is involved in measuring the rotation speed of the impeller (green or yellow fan wire). The fourth pin, corresponding to the blue wire, receives control signals from the PWM controller to adjust the cooler rotation speed depending on the temperature of the processor.