What's a Graphics Card?

Part (1)

السلام عليكم و رحمة الله و بركاته

The Purpose I wrote this article , that I found lot’s of people – even in our computer sceince dept. – don’t know what a graphics card mean .. what is the main components for a graphics card , How to compare between two graphic cards , Is can Graphics cards related to Games , and How Does it affect it ? … etc .. Lots of questions I try to answer insha’allh in this article.. I tried to grab the Most of info. From the internet .. to get you an accurate info. .. this topic is HUGE and it’s not enogh to cover all the aspects I one article .. so I’ll refer to some aspects in the other articles .. I hope u enjoy this article .. and if you have any questions .. feel free to cantact me ..Note: this article is ment for all people including sub-zero knowledge so form experts.. pleez be patient J .. now Let’s Go

The graphics card plays an essential role in the PC as an Graphical Output Device. It takes the digital information that the computer produces and turns it into something human beings can see. On most computers, the graphics card converts digital information to analog information for display on the monitor; on laptops,the data remains digital because laptop displays are digital .

If you look at the screen of a typical PC very closely, you can see that all of the different things on the screen are made up of individual dots. These dots are called pixels, and each pixel has a color. On some screens (for example, on the original Macintosh), the pixels could have just two colors -- black or white. On some screens today, a pixel can be one of 256 colors. On many screens, the pixels are full-color (also known as true color) and have 16.8 million possible shades. Since the human eye can only discern about 10-million different colors, 16.8 million colors is more than enough for most people.

The goal of a graphics card is to create a set of signals that display the dots on the computer screen.and to make 3D games so great giving you high FPS [ Frame Per Second ] and Amazing Quality.

What's a Graphics Card?

A modern graphics card is a circuit board with memory and a dedicated Proceesor. Graphics cards are known by many names, such as:

Video cards - Video boards - Video display boards - Graphics boards - Graphics adapter - Cards Video adapter cards

Today's graphics cards are computing systems in their own right. But these cards started out as very simple devices. By understanding the evolution of graphics cards, you can begin to see why they are so powerful today.

Graphics Card Components:

You can better understand the essence of a graphics card by looking at the simplest possible one. This card would be able to display only black or white pixels, and it would do that on a 640x480-pixel screen.

Note: Not All these Components are included in all Graphics Cards, But All of them are containes in all modern Graphics Crads :

GPU

The processor is designed specifically to handle the intense computational requirements of displaying graphics, Sometimes called GPU means [Graphical Processing Unit] , graphics processors have special command sets for graphics manipulation built right into the chip. [Hardwired Instructions on the GPU Chip] ,A simple graphics card, like the one described previously, is called a frame buffer. The card simply holds a frame of information that is sent to the screen. The computer's microprocessor does the job of updating every byte of video memory.

The problem with frame buffers is that, on complex graphics operations, the microprocessor ends up spending all of its time updating video memory and can't get any other work done. For example, if a 3-D image contains 10,000 polygons, the microprocessor has to draw and fill (render) each polygon in the video memory, 1 pixel at a time. This takes a while. Modern graphics cards have evolved to take some or all of this load off the microprocessor. A modern card contains its own high-power central processing unit (CPU) that is optimized for graphics operations. Depending on the graphics card, this CPU will be either a graphics proccesing unit or a graphics accelerator. Think of a GPU as a co-worker, and an accelerator as an assistant. The GPU and the CPU work simultaneously, while the accelerator receives instructions from the CPU and carries them out. In the GPU system, the graphics card driver software sends graphics-related tasks directly to the graphics coprocessor. The Operating System sends everything else to the CPU.

With a graphics accelerator, the driver software sends everything to the computer's CPU. The CPU then directs the graphics accelerator to perform specific graphics-intensive tasks. For example, the CPU might say to the accelerator, "Draw a polygon with these three vertices," and the accelerator would do the work of painting the pixels of the polygon into video memory. More and more complex graphics operations have moved to the GPU or accelerator, including Shading, Texturing, Anti-Alising,.. Etc I’ll talk about those terms in breif inthis article . These operations or Functions are commonly used by graphics programmers in Programming 3D Applications using API’s Like DirectX and OpenGL, these API’s must be supported or Hardwired by the GPU to accomlish good performance in exeuting it, but if it’s not supported .. the CPU hold all the Graphical Processing by Emulation nad that is a big drop in performance. L

There are 4 Major GPU Manufaturers at the Market which are Nvidia, ATI, Matrox and SIS, you may shouldn’t here all of these.. Because most people concerns about the Manufaturer than the GPU as an Example for there GPU’s :

1) Nvidia : TNT2 ,Geforce 256,Geforce 2,Geforce 3,Geforce 4,Geforce FX, Quadro FX… etc

2) ATI : Ati Rage 128 Pro,ATI@Xpert2000,Radeon 7500,Radeon 8500,Radeon 9000, …..

3) Matrox: G3, G4200, Prehilia .. etc

4) SIS : SIS 315 , Xabre 200 , Xabre 400 , Xabre 600 .. etc

May be when you have bought a graphics card.. you have noticed that 80% of people talk about the Card Manufaturer than the Kind Of GPU .. and that’s a big mistake … you always here ATI,Gigabyte , ASUS and they may say the Amount and the Kind of Memory on the Card like 16MB , 32MB , 64MB .. etc .

One on the Most imporatnt things to notice when you buy a graphics grad is the type of the GPU , Kind and amount of memory and then look at the Manufaturer [ ASUS,GIGABYTE , CHIANTEC .. etc ] .. because what happens in the reality is that the GPU Manufaturers seel the GPU to the Card Manufaturers then the Card Manufaturers buy the amount and of memeory that is compatible with the GPU and put their magical touch like TV-OUT , TV-IN , TV-Tuner , 3d-Glasses .. etc and they deliver you with some software for overcloaking [ increasing the speed of the GPU over it’s maximum limit ] .

Also if you want to measure the performance of a graphic card there is a lot of specifications to look for.. Most of these specifications are written on the Graphics Card Cover.. by this specs. You can compare between several GPU’s if you don’t know the specs of every GPU.. more detail abou this specs will be presented well at thisa article

As graphics cards and GPU’s continue to evolve, the capabilities become more and more amazing. Modern cards can draw millions of polygons per second. These features make it possible to create extremely realistic games and simulations.

In breif here is the main points of the GPU Functions:

#The graphics processor is the brains of the card, and is typically one of three configurations: #Graphics co-processor: A card with this type of processor can handle all of the graphics chores without any assistance from the computer's CPU. Graphics co-processors are typically found on high-end video cards. #Graphics accelerator: In this configuration, the chip on the graphics card renders graphics based on commands from the computer's CPU. This is the most common configuration used today.

Memory

The first thing that a graphics card needs is memory. The memory holds the color of each pixel. In the simplest case, since each pixel is only black or white, you need just 1 bit to store each pixel's. Since a byte holds 8 bits, you need (640/8) 80 bytes to store the pixel colors for one line of pixels on the display. You need (480 X 80) 38,400 bytes of memory to hold all of the pixels visible on the display. Memory types for Graphics Cards has several Kinds [ Sorted from older to newer ]

1- EDO RAM : 66 MHz

2- VRAM [ Video Ram ]: 100 Mhz

3- SDR RAM [ Single Data Rate ]: 100-133 MHz

4- DDR RAM [ Double Data Rate ]: 266-400 MHz

5- Dual DDR RAM [ DDR 2 ]: 1000 MHz

Computer Interface - The second thing a graphics card needs is a way for the computer to change the graphics card's memory. This is normally done by connecting the graphics card to the card bus on the motherboard. The computer can send signals through the bus to alter the memory.

Video Interface - The next thing that the graphics card needs is a way to generate the signals for the monitor. The card must generate color signals that drive the cathode ray tube (CRT) electron beam, as well as synchronization signals for horizontal and vertical sync. Let's say that the screen is refreshing at 60 frames per second. This means that the graphics card scans the entire memory array 1 bit at a time and does this 60 times per second. It sends signals to the monitor for each pixel on each line, and then sends a horizontal sync pulse; it does this repeatedly for all 480 lines, and then sends a vertical sync pulse. When a graphics card handles color, it does it in one of two ways. A true-color card devotes 3 or 4 bytes per pixel (4 bytes allows an extra byte for an "alpha channel"). On a 1600x1200-pixel display, this adds up to about 8 million bytes of video memory.

In the Next Issue Insha’ALLAH.. I’ll continue the journey … I hope the info in the 1^st part of the article was useful and has been presented in a an Easy and Rich with Information.

If u have any questions or any mistakes.. I’d be very pleased if you caontact me.. Feel free to cantact me at : motagaly@yahoo.com

Eng.\ Ahmad Salah