Factors Affecting Video Card Performance
To a newbie shopping for a video card, the long list of specifications and features on the card's packaging may seem like a foreign language. But hidden somewhere in all that geekspeak are important facts that can help you estimate how well the card will work for you.
The most important factors affecting video card performance include:
Type of Interface. At the time of this revision, the 16x PCI-e Version 3 bus is the current gold standard for video cards. AGP and PCI are both obsolete, although still available.
Amount of Video RAM. All video cards have at least some RAM on the card. The amount and speed of the onboard RAM has a major effect on the card's performance. For typing documents in Word, for example, you don't need a high-end video card with tons of RAM. Pretty much any video card that's supported by your operating system will do in that case. But for image manipulation, video editing, watching DVD movies, gaming, watching HDTV, or running CAD/CAM applications, more and faster RAM is needed. Many video cards sold as gaming video cards differ from oher video cards using the same chipsets mainly in the amount of RAM.
The amount of RAM needed for video is a function of the resolution, the frame rate, the color depth, the complexity of the raster, and the rate at which it's changing. The higher any of those factors are, the more RAM the video subsystem needs to keep track of it all, and the more processing power the GPU needs to crunch all those numbers that eventually result in what you see on the screen.
As of the time of this writing, my suggestions for video RAM for optimal performance at high frame rates in gaming or other video-intensive applications are based on screen resolution, and assume a frame rate of 60fps and maximum color depth. Using those criteria, I suggest the following as ballpark baselines:
- 720p screen resolution: 2 GB to 4 GB
- 1080p screen resolution: 4 GB to 6 GB
- 1440p screen resolution: 6 GB to 8 GB
- 2160p screen resolution: 8 GB to 12 GB
Yes, that's a lot of RAM. But I did say optimal performance. With the amounts of RAM shown above, you shouldn't encounter out-of-memory errors with even very complex screens. But you can probably get by with less most of the time. If your budget is tight and you can't affford that much RAM right now, you can try starting with a lower amount. Just make sure that your motherboard can support more in case you find you need it in the future.
3-D / Open GL Support. All but the very lowest-end video cards come with 3D and Open GL support. Open GL is the industry standard for high-performance video, and is supported on Windows, Mac, and Unix machines, as well as on many industrial and other specialized devices.
Cooling. All high-end and most mid-range video cards now come with their own onboard cooling fans. Adequate cooling makes a big difference when using the computer for gaming or other graphics-intensive applications. You also should lean toward bigger computer cases and extra case fans when building a box that will be used for graphics-intensive use. Heat is the enemy of all electronics devices. You need to keep that air moving through the case.