Comparison ASRock B650M Pro RS vs ASRock B650M-HDV/M.2

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 slots for DDR5 RAM, provided in the motherboard.

DDR5 is being introduced to replace the fourth version of the DDR standard from the end of 2020. It provides for approximately a twofold increase in memory subsystem performance and increased bandwidth compared to DDR4. Instead of a single 64-bit data channel, DDR5 uses a pair of independent 32-bit channels that work with 16-byte packets and allow 64 bytes of information to be delivered per clock on each channel. New memory modules require a voltage of 1.1 V, and the maximum volume of one DDR5 bar can reach an impressive 128 GB.

The maximum amount of RAM that can be installed on the motherboard.

When choosing according to this parameter, it is important to take into account the planned use of the PC and the real needs of the user. So, volumes up to 32 GB inclusive are quite enough to solve any basic problems and run games comfortably, but without a significant reserve for an upgrade. 64 GB is the optimal option for many professional use cases, and for the most resource-intensive tasks like 3D rendering, 96 GB or even 128 GB of memory will not be a limit. The most “capacious” motherboards are compatible with volumes of 192 GB or more - they are mainly top-end solutions for servers and HEDT (see “In the direction”).

You can choose this parameter with a reserve – taking into account a potential RAM upgrade, because installing additional RAM sticks is the simplest way to increase system performance. Taking this factor into account, many relatively simple motherboards support very significant amounts of RAM.

The ability of the motherboard to work with RAM modules that support XMP (Extreme Memory Profiles) technology. This technology was developed by Intel; it is used in motherboards and RAM blocks and only works if both of these system components are XMP compliant. A similar technology from AMD is called AMP.

The main function of XMP is to facilitate system overclocking (“overclocking”): special overclocking profiles are “sewn” into the memory with this technology, and if desired, the user can only select one of these profiles without resorting to complex configuration procedures. This is not only easier, but also safer: every profile added to the bar is tested for stability.

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.

The version of the M.2 interface determines both the maximum data transfer rate and the supported devices that can be connected via physical M.2 connectors (see the corresponding paragraph).

The version of the M.2 interface in the specifications of motherboards is usually indicated by the number of connectors themselves and by the PCI-E revision provided for in each of them. For example, the entry “3x4.0” means three connectors capable of supporting PCI-E 4.0; and the designation “2x5.0, 1x4.0” means a trio of connectors, two of which support PCI-E 4.0, and another one supports PCI-E 5.0.

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-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.