Like how the CPU is the brain of a computer, a graphics card is similar, but dedicated to just the display output of the system. It does all the calculations to draw your graphics on screen. Unlike a CPU it does these calculations in parallel, that is to say, instead of doing them one by one, it does them all at the same time. This means graphics cards can produce visual output extremely fast compared to running on the integrated graphics of a CPU. The result - better performance in your computer games.
Graphics Cards are dedicated to the visual output, they don't have to do anything else. Having one in your computer means you'll be able to run higher end games, faster. If you're a serious gamer, or even a casual one, there is no excuse to not have a GPU in your system
The Main Contenders
There are a couple of main manufacturers that produce basically all of the chips for graphics cards, which are then integrated with a cooling solution by other companies. These are:
AMD
NVIDIA
Intel
AMD and NVIDIA are the top two, with Intel recently launching their ARC series of cards to try and compete. We probably shouldn't have a favourite, but it's definintely NVIDIA who are in the lead at the moment. Their GTX and RTX series of graphics cards are unbeatable. Especially with the recent release of the RTX 5000 series that includes the monsterous GeForce RTX 5090 powerhouse. AMD aren't far behind, with Intel closely following up behind. In terms of pure performance for your gaming needs, Ray Tracing and AI features the NVIDIA RTX series cards are ahead by far.
RTX Series Graphics
RTX or, Ray Tracing Texel eXtreme is a feature of graphics cards that allows for the realistic similation of light in games and rendering. The name is all about Ray Tracing, but the cards are much more than that. They range from the lower end RTX 2050, 3050, 4050 and 5050 though to the top end at 2080, 3090, 4090 and 5090 series. Any of the cards, in any range will be better than using the integrated graphics on your processor. So if you're looking to up your game on a desktop PC. This is how you do it.
Beyond Gaming
Outside of gaming, graphics cards make video and photo editing faster and are fantastic for AI applications. Further, using them for hardware decoding makes video transcoding significantly faster. It's not just gamers who benefit!