Tips for Buying Right Graphic Card

Save some money for the CPU. If you spend all your money on graphics and skimp out on the processor, your system might score well on benchmarks, but won't fare as well in real game play (due to lower minimum frame rates).
Match your monitor resolution. Many mainstream cards are sufficient for gaming at 1080p resolutions and 30-60 fps, but you’ll need a high-end card for resolutions at or near 4K resolution with high in-game settings on the most demanding titles.
Consider your refresh rate. If your monitor has triple-digit refresh rates, you’ll need a powerful card to show its full potential. Alternatively, if your monitor tops out at 60Hz and 1080p, there’s no point in paying extra for a powerful card that pushes pixels faster than your display can keep up with.
Do you have enough power and space? Make sure your case has enough room for the card you’re considering, and that your power supply has enough watts to spare.
Check the MSRP before buying. A good way to tell if you’re getting a deal is to check the launch price or MSRP of the card you’re considering before buying.
Don't get dual cards unless you have to. Support for Multi-card SLI or CrossFire setups varies from game to game, and seems to be on the wane. Get the best single card you can afford.
Don’t count on overclocking for serious performance boosts: If you need better performance, buy a more-powerful card. Graphics cards don’t typically have large amounts of overclocking headroom.