Video Card Interfaces Explained: Physical Connectors (PCIe) and Software APIs (DirectX, Vulkan)

"Interface" refers to two distinct aspects of a graphics card:

1. Physical Interface (Bus Connector)

Connects the GPU to the motherboard.

• PCIe (PCI Express): Current standard. Versions 3.0, 4.0, 5.0 offer increasing bandwidth (x16 slots typical).
• AGP (Accelerated Graphics Port): Obsolete (late 90s/early 2000s).
• PCI: Ancient legacy standard.

2. Software Interface (APIs & Protocols)

How software talks to the GPU hardware.

• Graphics APIs: DirectX (Windows), Vulkan (Cross-platform), OpenGL (Legacy/Cross-platform), Metal (Apple). Drivers translate API calls to hardware instructions.
• Display Output Protocols: HDMI, DisplayPort, DVI, VGA. Define how the GPU sends video signals to the monitor.

Example Usage

• "This card uses a PCIe 4.0 x16 interface." (Physical)
• "This card supports DirectX 12 Ultimate and Vulkan 1.3." (Software)