AGP, PCI, Open GL, Direct X-  what the heck does it all mean?  Well, if you're in the market for a graphics card or a new computer, you'd better get an idea or risk buying something that  ultimately disappoints and wastes your money and your time.

The actual performance of a computer is no longer gauged solely by the CPU chip, in fact Intel Corporation, who has a vested interest in your buying the fastest chip they make, recommends that for graphic design you should concentrate more on the graphics card you choose than on the chip. Understanding the reason why they make such a recommendation requires that you become at least vaguely aware of what happens under the hood of your computer. In between keyboard and CPU chip and in between CPU chip and screen, numerous processes and numerous devices come into play.  For computer games, especially 3D games, video data is handled one way, and for graphic design, especially 2D design it is handled in another manner.

Looks The Same, Handles Differently

The majority of video acronyms you'll run into when shopping for a new graphics card or new computer, were developed to handle the massive data required by a 30 frame per second DVD video or for the constantly changing background of a 3D video game. It is literally impossible to handle the requirements of either category directly from the CPU, regardless of how fast it might be. For that reason, you'll find references to frame handling rates, trilinear fill rates and protocols such as Open GL and Direct X, which are all designed to better handle data transfer betwen the CPU, memory, and the graphics display device.  In many cases these devices are so specific that they must be accessed from the managing software, which is why if you are a Corel devotee primarily, such devices may not be of interest to you. Corel uses only a few of the many possible hardware device calls to display your work.

But, even when you have state of the art devices, the fastest CPU and the lastest software to handle those devices (drivers) there is still one additional component to be considered: the actual transfer mechanism, called a BUS.  Fast devices on a slow bus will still provide slow output- which is why we'll begin an exploration of video acronyms with the PCI and AGP category.

AGP, AGP/PCI  Your computers internal information highway.

To function, a computer requires some form of data transfer mechanism  (bus) so that computations from the main processor chip can be combined with data from the hard drive, from cache or from memory, and subsequently sent to a graphics display device or some other component, such as a sound card, to provide the results you see or hear.

PCI is the current base mechanism for standard PC data transfer. Often referred to as Personal Computer Interface, due to its ubiquitous usage, the acronym PCI is more accurately expanded to Peripheral Control Interface, as that is what it does.  It controls the peripheral devices including graphics display.

Think of the PCI as a freeway  for PC data, as virtually all data coming and going travels through this channel using the onramps and exits to and from various locations such as memory, hard drive, disk drive, keyboard, graphics display device, sound card or printer.

Taking the highway analogy one step further, PCI performance is measured in bits and Mhz. Think of the bit measurement as the number of lanes on your highway which determines the maximum number of cars that can travel on it. Think of Mhz. as the speedlimit.

And, continuing the highway analogy, there is a point where the highest number of cars travelling at the highest speed allowable will be reached, and you cannot add more cars (data) or speed (Mhz) so some travellers (data) may be waiting at the on-ramps for their chance to merge into traffic.

To solve the congestion problem, the industry has moved in several directions.  PCI-X is one alternative. The "X" stands for extended, and in our analogy, this would be like adding more lanes to a highway. PCI-X  can increase the maximum amount of data transferrable on a PCI bus (the physical transferrance device) from  532 Megabytes per second to 1.06. Gigabytes.

Another solution that has been embraced by the computer industry is AGP.  AGP stands for Advanced Graphics Port, AGP refers to the combined technology to build an extra data transfer channel to supplement data transfer, and in doing so to supplement the PCI. Moreover, AGP is restricted. In our highway analogy, this would be like building extra lanes on our highway that allow only trucks, or perhaps commuters with 2 or more passengers. Like an extra lane, AGP accomplishes two goals, it increases the amount of data that can be transferred by adding an additional transfer mechanism, and it reduces traffic on the standard PCI channel, allowing more non-video "vehicles.".

AGP also adds additional benefits besides simple bandwidth increase (more cars).  Because it is dedicated to video, links can be established directly between system memory, where image data may reside, and the video controller that will convert the data into a screen image. Without AGP this data would have to travel first to local memory before its transfer to the video controller. In highway terms this would be like taking a bypass (AGP) around congestion rather than going through town and stopping at several red lights (PCI).

AGP implementations may be 1X, 2X or 4X, determining  maximum amount of data transfer.  1X= 266 Mbps, 2X=  533 Mbps. 4X=  1.07 Gbps. When shopping for a device, remember that AGP increases data transfer speeds and it comes in three variations. If a product shows it is AGP compliant, without stating the "X" factor, assume it is an 1X implementation which can, at best, increase the PCI abilities by 50%, whereas 4X can literally triple them.

To make full use of AGP, all devices must work within the AGP protocols. The following are some of the common terms used in association with computers that can help you determine if a machine is configured in a way best suited for your needs.

   An acronym combining the first few letters of the words Compression and Decompression. A CODEC is used to compress, store and later decompress a video signal thus buffering the computer from the huge amount of data transfer provided by a standard TV video signal (more than 2 megabytes per frame, 30 frames per second).

Since CorelDraw and Photo-Paint screen output are usually not oriented to TV video, CODEC's are seldom a running concern, however CODEC's do come into play when importing or exporting video type files such as TGA, or various movie formats. Shown at right is the Dialog provided by Corel 10 to output an AVI file when compression is chosen. Normally, it is assumed that the CODEC chosen will be one used by another device on the same computer, such as Windows Media Player to display video.

Direct X  Direct3D  Direct X and 3D are MicroSoft APIs  or protocols that allow developers to write code that directly accesses hardware acceleration devices. Direct X is a constantly evolving protocol that has gone through a number of updates in the past few years. Direct X drivers also vary according to computer operating systems and are different for Windows 95.98/ NT and Windows 2000. Various components of Direct X would include names such as  Microsoft DirectDraw®, Microsoft Direct3D®, Microsoft  DirectInput®, Microsoft DirectSound®, Microsoft DirectPlay®, DirectShow®, and  Microsoft DirectMusic®

CorelDraw does make use of Direct X on the program level, by writing to the Windows API standard. Largely due to their (former) preference to write code directly transferrable to the LINUX operating shell for Windows, Corel's implementation of Direct X were of the "plain vanilla" variety, which does make integration to nearly any current system simple.

Driver:  A video display driver is the software that integrates the video hardware with your computer system. A video display driver can become outdated even when there has been no change in your computer hardware, due to the nature of ever evolving software and their reference and dependence upon constantly changing video standards and formats, such as Direct X. Video display vendors usually post the most current drivers for existing products on their WEB sites.  A driver can be replaced in one of two ways, depending on your computer system.  A direct replacement may be done by simply downloading and running an installation program to change driver attributes. Generally a reboot is then required to put the new driver into effect. For some computers, where display instructions are part of the BIOS or base operating system of the computer, a "flash" installation is required, wherein a bootable floppy disk with self-running program to change data at the bios level, is created during the boot process.

Dual Ported  When used in reference to a graphics diplay, the term refers to the dual transfer operation processes a video card can manage. A dual transfer allows transfer of data from video memory to the video processor over one channel, while simultaneously data is being transferred from the processor to the screen display on the second channel. Dual porting is required for nearly all high speed graphics processing.

MPEG II MPEG is an acronym for the Motion Picture Entertainment Group.  MPEG compression is used to transfer video data to a computer display.  MPEG II compression can provide resoultion of 720 X 480  or 1280 X 730 60 fps with full CD quality sound. MPEG II has sufficient resources to support even HDTV signals. MPEG would fall under the general category of CODECs (see above).

Corel Photo-Paint has supported MPEG as a filtering operation so that MPEG files can be loaded into Photo-Paint as a string of animation frames or saved from a Photo-Paint animation as the MPEG subformat of MPV (the video-only component of MPEG, not including audio tracks).

Note: Corel's implementation of the MPEG filter has been flawed and reports MPG MPEG output during a save process, but in actuality creates only MPV.

NLX  is the form factor of a PC, the determinants of physical size of a motherboard.  This refers to the motherboard's capability to handle memory modules and other mechanisms, including AGP devices. NLX is an improved form factor first offered in 1998.

OpenGL(R) is the software interface for graphics hardware that allows graphics programmers to produce high-quality color images of 3D objects.  OpenGL is a rendering only, vendor neutral API providing 2D and 3D graphics functions, including modelling, transformations, color, lighting, smooth shading, as well as advanced features like texture mapping, NURBS, fog, alpha blending and motion blur.

Open GL is not supported per se. by Corel products, nor would it be required despite the similarity of many rendering capabilities for bitmap images in Photo-Paint such as motion blur or texture mapping. Those Corel processes for bitmaps that are named similarly with Open GL attributes are actually processing functions within Corel to produce a single image, rather than producing a blur effect between two frames or more of a video display, as would be the case with Open GL.

For those also into computer gaming, however, Open GL is nearly a requirement, as it creates much more realistic and exotic displays as well as optimizing display capabilities.

NTSC  An acronym for the National Television Standards Committee.  This commission determines the protocol for standard television broadcasts in the US, NTSC, when used as a reference to "In" or "out" refers to the capability of converting the computer's RGB display to the composite NTSC format used for US televsions, or vice versa. In Europe, the dominant protocols are PAL and SECAM, which have slightly different resolution attributes.

Note: Computer display data is handled in a completely different manner from television display data, and crossovers must be run through filtering software or a filtering device-- see S-Video below.

Onboard:  In computer terms, this refers to a device residing on the motherboard of a computer. An onboard graphics display means that the graphics display adapter and related hardware and memory are already on the motherboard of the computer, thus freeing up a slot on the motherboard for other devices. Some, but not all, motherboards provide a mechanism in hardware and BIOS to turn the onboard graphics display ON and OFF. This allows you to upgrade the existing display if you wish. When there is no ON/ OFF mechanism, in most cases you cannot change or upgrade the video display qualities of your computer.

Onboard can also refer to items that reside on a particular device. For example, when a specific video card is references, onboard RAM will refer to RAM that physically exists or may be installed on that particular card.

RAM: An overview If you occasionally say "Time is money" then you might want to add to that "RAM is time"  The advantage of onboard RAM with a video card is time savings. Display information i/o is stored in onboard RAM in most cases until existing RAM limits are reached. Then, any subsequent data is stored on your hard drive. Symptoms of a need for additonal video ram are sporadic screen updates that proceed then stall, then proceed again as stored  data is accessed from your hard drive, and constantly flashing disk drive lights. Insufficient RAM can also lead to system lock ups and other failures when processes do not proceed within a time frame expected by software and measured on the system clock. Also, dependence upon hard drives for storage places data in a less secure area of your computer as hard disk space is monitored and verified less frequently and with less attentiveness to detail than onboard memory areas.

Tip:  You probably need more video RAM if you find yourself waiting long periods of time for file saves or screen updates in a Corel application.  You probably SHOULD upgrade video RAM if the cost of those wait periods in professional time equals or exceeds the cost of additional RAM.

RAMDAC  Random Access Memory Digital Analog Converter. Converts digital video signals to analog display.  Includes SRAM for color map storage and one DAC for Red, Green and Blue

S-Video  Though they may look the same, computer displays and TV displays are different. Computers displays utilize a single video signal for their display. Televisions use composite video, a dual signal with one signal determining luminance and the other determining chrominance. S-Video output means that the single RGB computer signal will be redefined to the composite dual signal required for television and video taping.

SGRAM  is an alternative to VRAM or WRAM, that uses only one port but can open multiple memory pages and synchronize to the system bus clock, effectively mulitplying throughput speed.

Trilinear fill rate.  This term is generally used to refer to a 3D graphics accelerators ability to generate X-number of triangle per second. This term is especially relevant for 3D based applications, especially 3D games where backgrounds are rendered as numerous colored triangles. The greater the trilinear fill rate, the faster background display data can be processed to be passed along to the graphics output device. .

VRAM or Video RAM  For video functions VRAM is more efficient than standard RAM in that it can be accessed by two channels so the RAMDAC can access data in VRAM while the graphics processor updates the data in VRAM.

WRAM, similar to but faster than VRAM since WRAM uses  Windows (the W- in WRAM) sized blocks of data, increasing the speed at which data can be transferred.

Armed with just a little bit of Compute Acronym knowledge you can trace the specifications of a particular computer through to see if you are getting a great device or a dog. If you would like more detailed information, there are several excellent sites providing basic tutorials on the inner workings of computer hardware. One such site we recommend is the AGP tutorial provided by Intel Corporation at http://developer.intel.com/technology/agp/tutorial/