Comparison Asus PRIME B550M-A/CSM vs Asus PRIME B550M-A

The maximum RAM clock speed supported by the motherboard. The actual clock frequency of the installed RAM modules should not exceed this indicator — otherwise, malfunctions are possible, and the capabilities of the “RAM” cannot be used to the fullest.

For modern PCs, a RAM frequency of 1500 – 2000 MHz or less is considered very low, 2000 – 2500 MHz is modest, 2500 – 3000 MHz is average, 3000 – 3500 MHz is above average, and the most advanced boards can support frequencies of 3500 – 4000 MHz and even more than 4000 MHz.

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.

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.

A four-pin connector for connecting a water cooling pump fan. It can also be used to turn on an additional CPU cooler.