Video Card Buyer's Guide

What are the factors we should bear in mind when buy a video card?

1.    The expansion slot on motherboard

Open the case of your PC. Check the expansion slot on your motherboard to see if there is AGP slot. It should be a dark brown slot between CPU and several rows of white PCI slots.

AGP vs PCI

The Accelerated Graphics Port (AGP) is a high performance, component level interconnect targeted at 3D graphical display applications. AGP is based on a set of performance extensions or enhancements to the PCI bus.

The AGP interface specification uses the 66 MHz PCI (PCI Local Bus Specification) specification as an operational baseline, and provides four significant performance extensions or enhancements to the PCI specification which are intended to optimize the AGP for high performance 3D graphics applications.

AGP neither replaces nor diminishes the necessity of PCI in the system. This high speed port (AGP) is physically, logically, and electrically independent of the PCI bus. It is intended for the exclusive use of visual display devices; all other I/O devices will remain on the PCI bus. The add-in slot defined for AGP uses a new connector body (for electrical signaling reasons) which is not compatible with the PCI connector; PCI and AGP boards are not mechanically interchangeable.

You also can view the manual of the motherboard to check the version of AGP and voltage. The more number of AGP version, the faster speed video card can run at. Please note the card should fit for right AGP version and Voltage.

AGP Modes  :                                                                                         

• 1x (266Mbps) (8 bytes per two clock cycles)                                               
• 2x (533Mbps) (8 bytes per clock cycle)
• 4x (1.07Gbps) (16 bytes per clock cycle)                                          
• 8x (2.1Gbps)  (32 bytes per clock cycle)

Connectors

• AGP 1.5v keyed

2. Memory of Video card

The video card controls what you see on your monitor. The memory on the card is used to store the images that you see on the screen. Most video cards today come with at least 64 or 128MB of memory. The more memory, the better performance the video card will make.  The type of memory used is usually SDR or DDR like the type of standard memory found in most computers today, as mentioned above - and sometimes running at faster speeds. DDR memory doubles the bandwidth and thus the throughput of your video card, and also raises the speed and price.

3.Speed - 3D vs. 2D

Nowadays, graphics processors, or GPUs (Graphics Processing Unit) to use the term thought up by nVidia, typically run at 200-350 MHz. Video memory can run at an effective 300-650 MHz by using DDR that really runs at 150-325 MHz and doubles its speed to (150-325 MHz)x2 for a faster effective throughput. Typically, the faster the chip and memory are running at, the better 3D performance you'll get. Most computer sellers don't focus on this information at all, but ask about it if you want the details. If you want a big monitor or multiple monitors, for 2D speed, you want a fast RAMDAC (or 2 or more) on your video card and plenty of memory. Most cards don't focus on 2D performance, but if you are moving big images around the screen, you will notice whether you have 2D performance or not.

4. LCD screens and DVI

If you plan to use a LCD screen with your computer now or in the future, you'll want a video card with a special output port on it called DVI (Digital Video Interface). If you purchase the LCD screen with your computer, most vendors will be sure to get you a card with a DVI interface, but it doesn't hurt to ask. You don't want some junky analog to DVI adaptor as you will not get a crisp LCD display. You can upgrade to a video card with DVI later if you need to, as well. Most computers still come with analog video cards standard.

5. Multiple displays

The most common option for multiple screens is dual-heads, or 2 screens. You will have to figure out whether you want 2 CRT monitors, 2 LCD panels, or one of each and match the appropriate video card with the proper outputs to it. Luckily, most vendors will figure all of this out for you. If you want more than 2 screens on your PC, you may have to go to a specialized vendor. The bonus to having multiple screens is screen real-estate. Play a movie on one, work on the other... or more realistically, work on both and use one as a reference screen and the other as your work screen. This is being written on monitor 2 of my setup. Having 2 screens is fantastic, but it takes up space, use more power, is complex and costs more money. It's worth it though if you use your computer a lot for complex work.

6. S-video and video in/out

As for other features, some video cards come with an array of video out options such as a composite (the yellow RCA type) video output, or an S-Video output. This is handy if you want to hook your PC up to a large color television for game playing or a VCR to record your gameplaying or whatever you wish to record or display. Other features include video inputs and TV compatible features. With this type of card, you can watch TV in a window on your computer monitor. Some people enjoy the integration if they spend long hours on the computer or require it if they work with video. TV features and the ports needed to use them are not common, but can be found if you look. It's also possible to add on a separate TV-card unrelated to your video card. For that matter, if you want to mess with digital video, make sure you get FireWire ports or a FireWire PCI card with your system.

Recommendations

For the best 2D and 3D performance, go with an ATI Radeon 9200 video card. It will cost you about $90 or so to do that, however. For the best balance of 3D features and price, go for the GeForce FX 5200.Both of the two support AGP8X. The ATI Radeon 9000 mixes nice Direct X features with a lower price. The GeForce4 MX card supporting AGP 2x or 2x/4x universal slot is basically a main stream video card. The cheaper ATI Radeon 7500 can be a bargain. What I would like to invite your attention is SIS’s chip. The Xabre400 series outperforms nVidia Geforce4 and ATI 9000 Pro in the 3DMark Performance test. The SIS 315 outperforms MX400 and ATI 7000 series.

The Worst and cheapest: Integrated video card with no AGP slot

In general, we recommend against buying a computer with video card built into the motherboard. Video card built into motherboards offer poor 3D performance, and are sometimes annoying to upgrade. If you are just buying a super-cheap computer and don't care, then that's your decision. If you happen to get integrated 3D graphics, at least make sure that there's an AGP slot on the motherboard so that you can upgrade your video card properly, and make sure you get plenty of RAM, as you'll be sharing that RAM with your video card. If you don't have one, your only option will be a PCI video card.