Increase in Computer Performance
The performance of your computer will surely increase by having a graphics card. This is because of the following two things:
1. Takes Load Off from CPU
An on-board graphics solution is generally dependent on CPU for all the graphical processing and calculations, so a part of the CPU remains engage in providing graphics, which can reduce the overall performance of a CPU and thus the whole system. A Graphics Card does not depend on the CPU and has its own GPU (Graphics Processing Unit) for performing all the graphics related operations and processing.
2. Free Up System Memory (RAM)
An onboard graphics solution takes up the system memory (RAM) for storing all the graphics information & data which can reduce a part of your total system memory. Whereas a graphics card has its own memory for performing all the graphics related tasks and processing.
Performance Increase in 3D Applications & Softwares
If you are a graphics designer or uses high end graphics and 3D applications like phototoshop, maya, heavy video editing tools etc. then having a graphics card can really speed up your work and you also get better performance & accurate results in these high-end graphics applications and tools.
Better Video and HD Experience
If you watch lots of HD and Blu-ray movies then a graphics card can really enhance your experience in watching high definition videos and movies.
Better Driver Support
A graphics card has better driver support for new operating systems, games and applications. This is because GPU manufacturers time to time releases latest drivers for their graphics card to keep them updated with the latest operating systems and games.