Comparison ASRock B550M Steel Legend vs ASRock B550 Steel Legend

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.

Standard digital indication system for displaying POST codes for motherboard initialization. Thanks to the POST encoder, you can easily determine which component has a problem.

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.

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 3.2 gen1 connectors provided on the motherboard.

USB connectors (all versions) are used to connect to the "motherboard" USB ports located on the outside of the case (usually on the front panel, less often on the top or side). With a special cable, such a port is connected to the connector, while one connector, usually, works with only one port. In other words, the number of connectors on the motherboard corresponds to the maximum number of case USB connectors that can be used with it. At the same time, we note that in this case we are talking about traditional USB A connectors; connectors for newer USB-C are mentioned separately in the specifications.

Specifically, USB 3.2 gen1 (formerly known as USB 3.1 gen1 and USB 3.0) provides transfer speeds of up to 4.8 Gbps and more power than the earlier USB 2.0 standard. At the same time, USB Power Delivery technology, which allows you to reach power up to 100 W, is usually not supported by this version of USB A connectors (although it can be implemented in USB-C connectors).

The number of USB-C 3.2 gen1 connectors provided on the motherboard.

USB-C connectors (all versions) are used to connect to the "motherboard" USB-C ports located on the outside of the case (usually on the front panel, less often on the top or side). With a special cable, such a port is connected to the connector, while one connector, usually, works with only one port. In other words, the number of connectors on the motherboard corresponds to the maximum number of USB-C chassis connectors that can be used with it.

Recall that USB-C is a relatively new type of USB connector, it is distinguished by its small size and double-sided design; such connectors have their own technical features, so separate connectors must be provided for them. Specifically, USB 3.2 gen1 (formerly known as USB 3.1 gen1 and USB 3.0) provides data transfer speeds of up to 4.8 Gbps. In addition, on a USB-C connector, this version of the connection can support USB Power Delivery technology, which allows you to supply power to external devices up to 100 W; however, this function is not mandatory, its presence in the connectors of one or another "motherboard" should be specified separately.

HDMI connector version (see above) installed in the motherboard.

— v.1.4. The earliest of the standards found nowadays, which appeared back in 2009. Supports resolutions up to 4096x2160 inclusive and allows you to play Full HD video with a frame rate of up to 120 fps — this is enough even for 3D playback.

— v.1.4b. A modified version of v.1.4 described above, which introduced a number of minor updates and improvements — in particular, support for two additional 3D formats.

— v.2.0. Also known as HDMI UHD, this version introduced full 4K support, with frame rates up to 60 fps, as well as the ability to work with 21:9 ultra-widescreen video. In addition, thanks to the increased bandwidth, the number of simultaneously reproduced audio channels has grown to 32, and audio streams to 4. And in the v.2.0a improvement, HDR support has also been added to all this.

— v.2.1. Another name is HDMI Ultra High Speed. Compared to the previous version, the interface bandwidth has really increased significantly — it is enough to transmit video at resolutions up to 10K at 120 frames per second, as well as to work with the extended BT.2020 colour space (the latter may be useful for some professional tasks). HDMI Ultra High Speed cables are required to use the full capabilities of HDMI v2.1, but older standard features are available with regular cables.

The version of the DisplayPort interface (see above) installed on the motherboard.

— v.1.2. The oldest version in use today (2010). It was in it that 3D support first appeared, the ability to work with the miniDisplayPort connector, as well as the option of connecting several screens in series to one port (daisy chain). The maximum resolution fully supported by v.1.2 is 5K at 30 fps, with some limitations, 8K video is also supported. And the v.1.2a update, introduced in 2013, added compatibility with the FreeSync technology used in AMD graphics cards.

— v.1.3. An update to the DisplayPort standard released in 2014. Thanks to the increase in bandwidth, it was possible to provide full support for 8K video (at 30 fps), and in 4K and 5K standards, increase the maximum frame rate to 120 and 60 fps, respectively. Another key update was the Dual-mode function, which provides compatibility with HDMI and DVI interfaces through the simplest passive adapters.

— v.1.4. The most recent version of the widely used. The bandwidth has been further increased (almost doubled compared to v.1.2, which allowed, albeit with some limitations, to transmit 4K and 5K video at up to 240 fps and 8K at up to 144 fps. In addition, Support for a number of special features has been added, including HDR10, and the maximum number of simultaneously transmitted audio channels has increased to 32.