The motherboard LAN port is either 568A or 568B, depending on your system requirements.
The motherboard LAN port is either 568A or 568B, depending on your system requirements.
The cable type isn't crucial as long as it uses the same RJ45 connector. Whether your socket is 568A or 568B depends on your motherboard, so you should check its specifications. For your B550M Pro4 model, you can identify the correct connector by consulting the manual or manufacturer guidelines.
Both and neither options are relevant here. The rules apply to the wiring, not the port itself. When cables match in quality on both sides, it's a straight-through connection. If one end has A and the other B, it's a crossover. (Transmit and Receive pairs connect together for 10/100 speeds.) Usually we don’t need to deal with this anymore since Auto MDI-X handles it automatically. Crossover cables are mainly useful if the auto-handshake fails or you’re using an older 10/100 port that doesn’t support it. In North America, 568b is the standard for consistency. Edited June 24, 2022 by Needfuldoer – clarification added after a shout from brwainer 
I remember when I was working in IT here in Vancouver, Canada. My boss told me that in Canada most folks type 568A, while in the U.S. people usually go with 568B. But honestly, both are fine!
Notice how the details change when you examine those sections closely. A cable designed this way only connects two out of the four pairs, not all. The belief around this comes from its actual crossover function for 10/100 Ethernet. Yet, pairing it with gigabit equipment won’t yield results. Modern gigabit devices often include Auto-MDIX, which adjusts automatically. This feature works for all four pairs simultaneously. When using an A/B cable with devices that have this capability, they continuously switch between modes and may settle on a slower 10/50 configuration. Early gigabit setups, especially the uplink ports on Cisco 2950 series switches, lack Auto-MDIX, so such a connection won’t function. If you need a genuine crossover cable for these devices, it must have all four pairs swapped—one end will clearly differ from both 568a and 568b.
You can buy a standard crossover cable at the same cost as a regular patch cable, avoiding cramped, bent wires in walls or panels that could cause problems later.
Consistently use a single standard for your horizontal movements.