When using the onboard video option of your SilentPC.com computer, your graphics capability is determined by the processor you choose, and your video ports are determined by your motherboard's onboard headers.
The latest Onboard-CPU graphics are quite well suited for common PC usage. In fact, previous generations of performance graphic processors (using GDDR3) were right in line with the latest graphics available from Onboard-CPU. Still, depending on the purpose of your PC (mainly for graphics use and light office work, or do you like to process photos and do a little video work), purchasing a higher-end CPU can result not only in better CPU performance, but in better video performance.