Graphic card chipset info

The Graphic Chipset:

The graphic Chipset might be considered as the heart of the graphic card. As a fact the graphic Chipset is controlling every essential operations of the graphic card.

The way to determine the quality level of a graphic Chipset is by its maximum bandwidth. The bandwidth of a graphic Chipset is simply the width of its data path. Nowadays, there are two type of graphic Chipset in use and these are the 128-bits Chipset and the 64-bits Chipset. Like you probably guessed the 64-bits Chipset are the older one and they are in use since about 5 years. Until recently some 64-bits based Chipset were used by some graphic cards outperforming many of the newest 128-bits Chipset but now things have a tendency to equalize and as a matter of fact many of the 128-bits Chipset based graphic cards are now outperforming 64-bits Chipset which is a just return to the normality.

For many reasons some graphic Chipset are offering better performances under a Windows environment while some other are performing best under DOS environment but this cant unfortunately be established when its time to buy a graphic card unless you have some benchmark results to compare the cards you are interested by soit would be well advised to look at a large graphic card benchmark comparison listing before to go to the store so you can make sure that the graphic card you will buy is performing best under the operating system you will be using .


The RAMDAC:

earlier the RAMDAC is the circuit used to convert the digital signal of the graphic card into an analog signal that can be feed to the graphic monitor. The ability for the RAMDAC to accomplish this process is what determines its quality and this quality factor of the RAMDAC has a very important effect on the overall performance of the graphic card. The quality indices of a RAMDAC is expressed in MHZ. Before to go any further I would like to give you the terminology of these two words:

RAMDAC: stands for Random Access Memory Digital to Analog Converter

MHZ: stands for Million cycle by second

The RAMDAC frequency measured and expressed in MHZ simply means the number of operations this circuit can accomplish in a period of time of one second.

To understand this there is a very simple way and I'll explain it. Every time a new image is processed by the graphic card circuitry it has to be converted by the RAMDAC to be feed to the monitor. As a matter of fact new images are constantly feed to the monitor even if nothing changes of your monitor screen because the monitor screen needs to be refreshed at a frequency corresponding to its refresh rate but I'll come on this with more details later on this page.

Now, the amount of data that must be converted by the RAMDAC is directly related to the color resolution used by your applications multiplied by the refresh rate used plus an additional factor which has to be taken into account for the time that the cathode ray guns are tracing outside of the visible area of the monitor screen and this factor is 1.32.

According to this a formula can be defined to make this calculation like following:

MHZ = (Vertical resolution X horizontal resolution X refresh rate) X 1.32

For instance suppose we have a screen resolution of 1600 X 1200 and we will use a refresh rate of 85hz. Using the formula we will be find that a RAMDAC frequency of 1600 X 1200 X 85 X 1.32 = 215.4mhz will be required to adequately process this screen resolution at this refresh rate.

Like you can see the use of this simple formula can allow you to make sure the highest resolution and refresh rate you would like to be supported by the graphic card you intend to buy will be effectively supported by the RAMDAC installed on this graphic card.