would a bulit in Intel HD Graphics card have a lower latency

than a discrete graphics card such as an Nvidia or Radeon since its built right into the processor?

http://www.intel.com/technology/graphics/

Lower latency maybe. Depending on how you define that. There will be some added delay schlepping data onto a bus to get it to a plug-in graphics card. How that would relate to overall performance is a question that I expect depends on how you define performance, and what you are asking your graphics card to actually do. The big advantage to using a graphics computer (video card) plugged into your main computer is that it can do a lot of the calculation needed to create realistic full motion 3-D video without bothering your CPU much. That graphic processing power is not the same as low latency, and low latency by itself does not imply much about processing power.