What is it?

As the name would suggest, the graphics card is an extra processor specifically dedicated to generating graphics. It is important for any program with a graphic output (so almost any program) and absolutely necessary for anything that requires 3D models, including games and modeling software such as Blender.

 

 

What specs should you look out for?

• GPU: Similar to CPUs, the Graphics Processing Unit (GPU) in a graphics card is produced by one of two companies: AMD or Nvidia. Most competing GPUs will have similar features under different names.
• Stream Processors/CUDA Cores: The individual computing units in the GPU. This may not accurately reflect the processor's performance, as its architecture can also effect the efficiency of its cores.
• Memory: A graphics card has its own integrated version of RAM called GDDR. Deciding factors for memory should also be considered here. 
• Display Outputs: Graphics cards will usually have a number of display outputs on their back side, including HDMI ports and DisplayPorts.
• TDP: Just like with CPUs, TDP can be used to find the expected power needs and operating temperature.
• PCI-E Version: It is important that the versions of PCI-E on both your graphics card and motherboard match, otherwise one will end up throttling the other.