- Laptops use a different formfactor of graphics cards. They use GPUs built into the CPU, or have a modular discrete GPU extension card built into the system. A modular GPU may be replaced with one that is compatible with the laptop (compatibility between various laptop GPUs and laptops is not guaranteed).
- GPUs for laptop system can physically not be connected to a desktop.
- GPUs for desktop systems can physically not be connected to a laptop.
- Not every laptop has the required connection for a GPU card.
Example of a laptop GPU:
Example of a destkop GPU: