There are plenty of different ways to connect devices to your gear.
You really want a direct connection to the motherboard for the CPU, SSD, RAM, and GPU.
To get the most out of these devices, motherboards feature connectors directly, with no cables involved.
For RAM and GPUs, the physical connector on the motherboard is called a slot.
The other defining feature of a slot connector is that the equipment it holds sits perpendicular to the motherboard.
To this end, the main factor in physical compatibility is the position of the key.
The key is a cutout from the connector and cut into the slot.
In each generation of DDR RAM, the key position has moved.
This ensures you cant plug a DDR3 RAM stick into a DDR4 slot.
It also means that RAM sticks can only be plugged into the slot one way around.
The RAM slot offers many electrical connections for the RAM stick.
The two clips must then be manually pushed apart to release the RAM stick.
Design
Motherboards are carefully designed and laid out.
RAM slots are always placed as close to the CPU socket as possible.
This is to minimize the distance the signals need to propagate.
RAM is very latency-sensitive, so shorter connections provide the lowest possible signaling latency.
This synchronization is vital as RAM works on a clock that ticks millions of times per second.
Most CPU coolers are designed to at least allow standard-height RAM sticks.
Some CPU coolers may interfere with them even if they dont have heat spreaders, increasing their height.
RAM and other devices have been carefully designed to use connectors that are not physically compatible.
Its impossible to put RAM in a PCIe slot or vice versa.
The easiest different gear to get mixed up with is the DIMM.2 SSD.
This takes a similar form factor and slot to RAM but is an SSD.
Again though, DIMM.2 SSDs will not go in RAM slots and vice versa.
They are carefully designed only to be physically compatible with the proper generation of RAM.
The slots also feature an automatic retention mechanism at either end.
Care must be taken to loosen this before removing the RAM.
