Network card
Network Interface Card is the card that physically makes the connection between the computer and the network cable. The cards generally are available in 10, 100 and 100 Base-T configurations. A 100 Base-T card can transfer at 100Mbps.
graphics card
Majority of the processing done on a computer is done via the CPU. In order to ease the work of the CPU and allow the CPU to work more efficiently, a graphics card can be put in the computer and can be used to process the graphics portion of the processing load. Graphics cards also called Graphics Accelerators can speed up both 2D and 3D graphic rendering. Graphics cards are typically installed in either the PCI or the AGP slots in the back of a computer.