Looks like this may be a video card problem
In my expereince, it can be many things and you just have to elmenate all possible issues.
1. Design - How you may have designed the component can effect the speed of the rebuild. I always get reminded that a properly modelled component is key. So go to Evaluate>Statistics (May be different, depending on how you have set up your UI) and a small new window will appear which showcases the rebuild time of each feature in the CAD Model. Normally the rebuild time for each feature is computed at mille seconds but these build up and can cause an elongated rebuild time.
2. Hardware - Everyone ask what the best computer setup for a CAD workstation. There are so many different variations and solutions for particular situation that they won't all work for you. However a general rule of thumb is to have a setup with a high RAM, processor with a high clock speed, 64-Bit OS, and a dedicated Graphics card.
Hope that helps, maybe the first solution, will reduce the dependancy on needing to spend any capital.