Though integrated graphics systems are more commonplace today than ever, even the best versions in the latest processors can’t deliver what you can get from even a lower-end discrete video card. If you’re into gaming of any sort, a video card is a must, but any programs that are designed to do so, from Windows to Photoshop and beyond, can benefit from offloading video processing to a dedicated subsystem. Unless you’re blasting out a tight budget build, there’s no good reason to forego a video card.
What to look for?
Processing cores. Like your CPU, your graphics processing unit (or GPU) contains multiple processing cores exclusively for churning out graphics. The more of them your video card has, the better a performer it’s likely to be (and the more it’s likely to cost). AMD calls its versions “stream processors” and Nvidia has named its own “CUDA cores”—note that while you can’t directly compare the two types, the numbers of cores are good indicators of relative power within each company’s chipset families.
Clock rates. As with your CPU, this is the speed at which the GPU runs. It’s not unusual to see cards with fewer processing cores and faster clock speeds, or vice versa, so finding the best blend for the amount of money you have to spend is a good way to go.
Memory. Video memory (VRAM) serves a function for video cards that’s similar to what ordinary RAM does for the rest of your computer: It stores the data until it’s needed for processing. This matters less if you’re playing at lower resolutions, where there aren’t as many pixels and other visual effects to be wrangled, but, as a rule of thumb—as with…RAM—more tends to be better. (You’ll see 4GB or more on the highest-end, most expensive video cards.) Also watch for the memory clock speed, which can also factor into performance.
Ports. A video card isn’t worth much if it’s not hooked up to at least one monitor. Look at the list of its ports to determine what sort of outputs your card has for DVI, HDMI, and DisplayPort; if you’ll be using your computer with a monitor you already own, you’ll want to know ahead of time whether you’ll need to buy an adapter. Another good idea is verifying how many monitors the card can drive at once: It may not be the same as the card’s number of output ports.
Power requirements. Video cards are among the most power-hungry PC components you can buy, so know what you need to get from your power supply. Usually there will be a minimum value you should respect, and you’ll also be told the specific number of connectors (six- or eight-pin) you’ll need in order to get the card to work as well as the number of amps needed from the power supply.