How do discrete graphics cards typically connect to the motherboard?

Discrete graphics cards connect to the motherboard primarily through a PCIe (Peripheral Component Interconnect Express) or AGP (Accelerated Graphics Port) connection. PCIe is the current standard and offers high bandwidth, allowing for fast data transfer between the motherboard and the graphics card, which is essential for high-performance graphics and gaming applications. AGP was more common in older systems before the widespread adoption of PCIe, and while it supports graphics data transfer, it is now largely obsolete.

In contrast, options such as USB and Thunderbolt are typically used for peripheral devices rather than internal connections for components like graphics cards. USB connections do not provide the necessary bandwidth for gaming or high-resolution video output. Meanwhile, Ethernet ports are intended for network connectivity, making them unsuitable for connecting a graphics card to a motherboard. Thus, the PCIe or AGP connection remains the relevant and correct method for discrete graphics card integration.