Why is the GPU Installed in the mid-board PCIe Socket?

If you have ever had to mount a PC (or have seen yours inside) you will have noticed that the graphics card is installed practically in the center of the motherboard, and due to its size it is quite a hindrance, even creating problems compatibility. Why does the motherboard’s PCIe socket force us to install the GPU in the middle ? We explain it to you below.

The arrangement of the PCIe socket on the motherboard forces us to install the graphics card almost in the center of the system, and due to the size of this component we often have problems channeling the cables (such as its own PCIe power connectors) and It even creates compatibility problems with too large CPU heatsinks, with M.2 SSDs that have their own heatsink and sometimes even with the motherboard’s own heatsinks. Why then is it located in this position and not at one end of the motherboard?

GPU Motherboard

The PCIe socket layout on the board and the GPU installation

There are several inconveniences that installing the GPU in the upper PCIe socket of the motherboard creates, such as:

  • Potential incompatibility with the processor heatsink.
  • Difficulty routing PCIe power cables.
  • Potential incompatibility with SSDs in M.2 format.
  • The heat from the GPU heatsink meets that of the CPU heatsink.
  • Problems channeling the HD Audio cable due to the connector layout on some boards.

CPU graphics problem

Most ATX format motherboards have multiple PCI-Express x16 sockets, and that means we could technically install the graphics card, for example, in the bottom socket, the furthest away. However, in most cases this would pose another additional problem because since most graphics cards occupy at least 2 PCI slots, the connection ports of the motherboard such as the front panel or USB connectors would be covered, which many sometimes it makes it impossible to use this bottom socket (and in fact many boards have a PCIe x1 socket there instead of a x16).

That the main PCIe socket is in the center has its reasons

When engineers have to design the layout of the components on the motherboard, they must take many factors into account, and obviously the space that the graphics card will occupy in the main PCIe is one of them but not necessarily the most important. The motherboard’s PCIe sockets are necessarily in constant communication with the processor, and this is the main reason: the closer it is, the less travel there will be between one and the other and therefore the communication latency will be lower .

PCIe 6.0

In the end, when they design a product as extremely complicated as a motherboard, they must often choose a lesser evil in order to improve other faculties, and this is precisely what happens with the arrangement of the PCIe socket of the motherboards, located everything glued to the socket which can be taken into account the design of both CPU coolers and graphics cards.

Obviously, they could also choose to swap the positions of the DIMM sockets for RAM with the main PCIe of the graphics card, making the GPU positioned closer to the socket. However, we return to the same problem, since it is important that the RAM has the best possible latency with the CPU, even lower than the GPU, which is why these sockets are as close to the socket as possible. In addition, if you do so, the video outputs of the graph would be facing upwards while the rest of the ports on the board would be behind, and it would be quite uncomfortable to call it somehow.

So that the PCIe socket for the GPU is in the middle of the motherboard has its reason for being, and this is the latency. The closer the PCIe socket is to the processor socket, the shorter the time it takes to communicate between the two (latency).