ViewportFrame and Workspace accuracy difference help

While in the process of figuring out what to go for in an FPS engine script, I am struggling to find an answer to these questions after trying to find one. My question lies with the following:
If I have two anchored parts, with one in workspace and the other in a viewport frame, which one’s positions would be more accurate over time?
If I have two unanchored parts, with one in workspace and the other in a viewport frame, which one’s positions would be more accurate over time?
If there’s a similar post, my apologies, but I cannot find any similar posts to answer my question.