While most standard computers come with a built-in GPU (Graphics Processing Unit), video-intensive activities such as graphic design, HD video editing, animation and PC gaming will likely require a dedicated graphics card to provide the performance you desire. A more robust graphics card provides more optimal graphics displays and faster refresh rates, for a higher level of realism for your games or detail in your designs. 

For the most part, the more powerful the GPU you're using, the better the results. The performance indicator of each graphics card is identified by its model number. So generally, the higher the model number, the better performance you can expect from your graphics card.

There are many video graphics cards available, and the one you choose will largely depend on how you want to use it, what types of PC games or software you're interested in using, and how much you want to spend. Installing a new graphics card is not a difficult task as long as you select the right one to fit your existing system as well as your needs. 

Upgrading your GPU may not provide the boost you were hoping for if you have a weak processor, a poor quality display, insufficient power supply, too little memory, too small a case or even poor cooling capacity. For that reason, look at the graphics requirements of the games you want to play, or the software you want to run, to see what is required or suggested, then use that as a baseline for selecting your new card. Also, be sure to measure to make sure the card you select will physically fit in the case.