Theory - 23 :- What is a Graphics Card? Major Components of a Graphics Card

Graphics Processing Unit (GPU) & Graphics Expansion Cards

Comprehensive ICTSM 2nd Year (Semester III) Theory Notes

Trade Theory GPU Architecture Hardware Maintenance

1. Introduction to Graphics Cards

A Graphics Card (also called Video Card, Display Adapter, or GPU Expansion Card) is an internal hardware component responsible for processing visual data and rendering images, 3D graphics, animations, and high-definition video directly to a monitor.

Core Operating Concept: The graphics card offloads complex parallel graphical computations from the main system CPU, utilizing high-speed dedicated video memory and parallel processing cores.

Figure 1: Graphics Data Processing Pipeline Flow

1. System CPU

Sends 3D instructions & render commands

➔

2. GPU & VRAM

Processes shaders & builds frame buffer

➔

3. RAMDAC / Encoder

Converts data for display output

➔

4. Display Unit

Renders screen image (VGA/HDMI/DP)

2. Types of Graphics Cards

1. Integrated Graphics (iGPU) Built-In

Embedded directly inside the CPU processor package or motherboard chipset.

• Shares main System RAM memory
• Low power consumption & minimal heat
• Suitable for office applications, web, & video playback
• Cannot be easily upgraded

2. Dedicated / Discrete (dGPU) Expansion Card

An independent hardware expansion board plugged into the PCIe x16 motherboard slot.

• Uses high-speed Video RAM (VRAM)
• Active cooling heatsink & fan assembly
• High performance for 3D gaming & video editing
• Easily upgraded or replaced

3. Major Internal Components

A discrete graphics card consists of several primary onboard hardware components:

• GPU (Graphics Processing Unit): The core processor chip containing hundreds or thousands of small cores designed for parallel matrix calculations and shader processing.
  • NVIDIA: CUDA Cores
  • AMD: Stream Processors
• GPU Clock & Shader Frequency: The operational speed (MHz/GHz) at which the GPU core and parallel shaders execute instructions.
• Video RAM (VRAM): Dedicated high-bandwidth memory (GDDR3, GDDR5, GDDR6) used to store textures, 3D geometry, and framebuffers.
• RAMDAC: Random Access Memory Digital-to-Analog Converter. Converts digital image data into analog signals for legacy VGA output.
• Cooling Assembly (Heatsink & Fan): Combines passive metal heatsinks with active axial fans to dissipate heat from the GPU core and VRAM chips.
• PCIe x16 Interface Connector: High-speed gold pin edge connector that inserts into motherboard PCIe expansion slots (replacing legacy AGP interface).
• Auxiliary Power Connectors: Additional 6-pin or 8-pin power sockets used by high-performance cards to draw extra +12V power directly from the PSU.
• External Video Output Ports: Interfaces used to connect monitors:
  • VGA: Legacy analog video port.
  • DVI: Digital video interface (without audio).
  • HDMI / DisplayPort: Modern digital ports carrying high-definition video and audio signals.

4. Physical Component Board Layout

Below is the architectural mapping of a discrete graphics expansion card board:

Figure 2: Graphics Expansion Card Board Layout

Display Ports

HDMI

DisplayPort

VGA / DVI

VRAM

VRAM

VRAM

GPU CORE

VRAM

VRAM

VRAM

VRM Power Phase

6/8-Pin Auxiliary Power

PCI Express x16 Gold Connector Interface (Motherboard Connector)

5. Component Functions Summary

Component	Main Function	Key Metric / Specification
GPU Core	Processes parallel graphics calculations & shader pipelines	Core Clock (MHz/GHz), Core Count
VRAM Memory	Stores textures, depth buffers, and rendered framebuffers	Capacity (GB), Bandwidth (GB/s), Type (GDDR5/6)
RAMDAC	Converts digital frame data into analog video signals	Clock Speed (MHz)
Cooling System	Prevents thermal throttling by cooling GPU core & VRMs	Fan RPM, Heatsink Surface Area
PCIe Bus	High-speed communication interface with CPU & System RAM	PCIe Gen 3.0/4.0/5.0 x16 Lanes
Power Sockets	Supplies dedicated +12V power directly from PSU	6-pin (75W) / 8-pin (150W) connectors

6. Troubleshooting & Maintenance for Trainees

Technicians must diagnose common faults related to graphics adapter failures:

• No Display / Blank Screen: Ensure card is fully seated in PCIe x16 slot, verify auxiliary 6-pin/8-pin PCIe power cables are connected, check monitor cable.
• Screen Artifacts (Visual Noise): Dots, lines, or corrupted screen textures usually indicate overheating or failing onboard VRAM chips.
• Thermal Throttling / Excessive Fan Noise: Caused by accumulated dust in heatsink fins or dried GPU thermal paste. Solution: Clean with compressed air and reapply thermal paste.
• Driver Crashes / BSOD: Corrupted or outdated GPU display drivers. Solution: Boot in Safe Mode, use DDU (Display Driver Uninstaller), and reinstall latest official drivers.

NCVT Exam Revision Points:

• GPU Full Form: Graphics Processing Unit
• VRAM Full Form: Video Random Access Memory
• RAMDAC Full Form: Random Access Memory Digital-to-Analog Converter
• Expansion Interface: Modern discrete graphics cards use PCI Express x16 expansion slots (replacing legacy AGP slots).
• Major Chip Manufacturers: NVIDIA and AMD (ATI).
• Multi-GPU Standards: NVIDIA SLI and AMD CrossFire allow multiple graphics cards to work together for increased performance.