A video card is the thing which produces or renders the output from the computer. It works between the processor and the monitor. Earlier the processor used to compute all the values and things of which pixel should b darkened and all. When DOS was used this was okay, because there weren’t many pixels that were being worked on. So at those times, the video card would just let the processor do all the calculations and translate it to something which the monitor would understand.
When using DOS this was very much acceptable. Because the processor did not have much to do and the processor was soooooooooo powerful. But when something like Windows comes up, there is lots’ graphics and stuff on screen, windows, Icons, cursors, buttons…and lot of applications. So the processor sitting and calculating size of window and all was useless. It had better things to do.
So the work of the video cards would be redefined: now on the video card would do all the calculation of VIDEO reqs (obviously)...and they were rechristened as ACCELERATORS. So now the processors would do their own calculations (all things we studied in CO,MUP, A-MUP,B-MUP,C-MUP, …u know where I am getting) and the video accelerator would sit and draw beautiful things on the display.
Video chipset
These days, the video card has an internal processor on the card and it is this processor that does the calculations. The LOGIC CIRCUIT (LSD S4, CHD S5…etc) that controls the video card is referred to as the video chipset (sometimes called the accelerator). The main chipset providers today are: Nvidia and ATi. These are the guys who make the chipsets for a large majority of the video cards. Nvidia(www.nvidia.com) and ATi(AMD bought ATi a few months back and rj is very close to both of them :-p so ati.amd.com) bring out their own cards, but this doesn’t mean that there are only two companies that make video cards. There are hundreds of them, it’s like assembling diff IC’s and chips together but in the end they use the chipset provided by ATi or Nvidia.
Video Memory
Just as a computer needs memory (RAM) for its operation, video cards also need memory for proper functioning….more video memory faster that pic of the chick loads, faster and smoother a game runs and better will be your ‘movie’ experience. These days a lot of video memory is needed, so the memory is put on the card itself. The good thing about this is that, this memory can be just used to do video rendering and stuff and system memory would not be needed.
Some motherboard designs integrate the video chipset into the motherboard itself, and then use part of the system RAM for the frame buffer. This is called unified memory architecture. This is used only because users like you and me are beggars and would not want to shell out Rs.5, 000 or greater on a video card. This is a very sensible thing also, cos not many ppl need more than say, 64MB of video ram. This leads to other things like AGP,SLI, SLI express and all, which will be too much to digest right now(for you and me).
RAMDAC (don’t get bored by the heading, it makes sense to you, a CS student)
RAMDAC = RAM + DAC
= Random Access Memory + Digital to Analog Converter
The image to be shown on screen is stored as 0’s and 1’s and they store colour, intensity and other details (CG, S6) but the monitor is not smart enough to know the 1’s and 0’s. It has to be fed analog data. This is where the RAMDAC comes in…Digital to Analog Converter (time to thank Koshy sir). The RAMDAC reads contents of the video memory, converts it to analog and sends it to the monitor.
A fact: It is the RAMDAC of your card that determines the max. Resolution, refresh rates, number of colours that can be displayed.
Well this is just the basic of what a video card is…and I will tell you how the main memory is shared for video purpose.
Situation: Video card has only 64MB ram, more video ram needed. Got 512MB of system RAM (normal ram). But 512MB is not always used.
Solution: share a part of 512MB with the 64 MB video ram…make video RAM 128MB by taking 64MB from main memory
Effective RAM: 512-64 = 448 MB
Effective video RAM: 64+64 =128 MB
So, now the issue of lack of video memory also solved. This is why even if you have 512MB memory in your system, it shows lesser than 512 or whatever you have.
Thing to do (it’s always better if you see things yourself, so do this and see for yourself and its just THING and not THINGS....pleez pleeez pleeez do this):
-Go to Run from Start menu
-Type in ‘dxdiag’ and run it
-The DirectX diagnostic tool comes up (no worries, dad wont scold you, and your computer won’t become a ball of fire within the next 5 seconds)
This is one tool that gives all the info that you need about your system in one place, and it’s easy to get there also. Go through it and understand your computer…and check out which version of direct X you got…the latest one is dX 9, get it if you don’t have it… chk out all the tabs display,sound1,sound2…there are tests that you can do also….the ‘square box’ text is particularly interesting ;)
Hope you understood something and really hope you did the Thing to do…. Doubts, queries.. anything…ask me or anyone…better that you ask it in da comments section here, or in an open forum, cos dat way more ppl will get to know more things and we will all be ppl who know more things.
Scope for further study or blogging :AGP,SLI, SLI express
Reference ( actually whole thing almost copied and put in my own words) :
Just in case pics weren’t clear :
http://static.howstuffworks.com/gif/graphics-card-5.jpg
http://home.wlv.ac.uk/~c0384877/graphics%20card.JPG
AND its so bloody hard to get this thing formatted on blospot.com .... :(
