Form factors
Motherboards tend to have a basic layout, they different on expansion and memory slots usually.
However, power connectors are fairly standard.
In general, we choose motherboards based on cases or expansion, or due to airflow depending on the workflow.
ATX (Advanced Technology Extended)
Standard ATX is the most common desktop computer motherboard. They have had many updates, where power connectors are 20 / 24 pins with additional power for the CPU
ITX
These boards are much smaller, and may often be used for SFF media centers. Oftne also used for low-power operation.
Used for single purpose computing, like streaming media.
Compatibility
Expansion Slots
A computer bus is required to connect all different parts of a motherboard to connect different devices on it.
PCI
Perripheral Component Interconnect
PCI buses uses parallel communication in 32-bit and 64-bit buses.
These connect to a controller hub on the motherboard.
The expansion cards also support different voltages - 3.3 V or 5V
We know a card is 64-bit because it has an additional key and contact at the back of the card
PCIe
This replaces the PCI bus, and is more commonly seen on modern machines. This changes the set up of parallel connections into a set of serial connections. the serial connections are known as “lanes” and they are designed such that a slower device won’t slow the operation of every other device.
You can add more lanes to a PCIe bus to support more data, between x1, x2, x4, x8, x16, x32.
A single lane is actually two way-roads, fi you will.
Connectors
Power
3.3V +-5 +- 12
Historically used 20 pins, but higher power requirements have switched into a more common 24-pin connector.
The connectors are keyed such that the connector annot be inserted in the wrong orientation.
Make sure you disconnect from all power sources before plugging in.
CPU
CPUs use 4-pin ATX connectors providing 12V power. Mayb be labelled P4, CPU, or ATX12V.
SATA
Headers
These are also referred to as pin-headers. They have many uses, such as power, peripherals, lights, buttons, etc.
AAFP → external audio connectors
Front panel
These are integrated into the motherboard via connectors provided on the case; these are connected into the motherboard on the headers.
Compatibility
CPU
The motherboard is often dependent on the CPU manufacturer we choose. The main ones are Intel and AMD.
In general AMD tends to be slightly cheaper.
They have different sockets, and as such the decision for one or the other CPU will have consequences for the rest of the system. Historically, AMD is value and Intel is performance, though this does change.
Server motherboards
These motherboards will often support multiple physical CPUs to distribute compute load, in addition to 4+ memory module slots and many expansion slots.
Often installed in a rack-mounted ATX case.
Desktop motherboard
Desktop systems generally have a single CPU, two to four memory slots, and just a few expansion slots. They can also be fully integrated into the monitor.
Mobile motherboards
These are generally the smallest motherboards we see. They CPUs are generally designed for weight and efficiency, but they often suffer from thermal throttling.
They have the least amount of modification and expansion available.
Laptop motherboards are often proprietary and built for a specific model; as a result, their replacement isn’t easy since we must replace the entire thing.