Impact Graphs have received an upgrade that enhances render times, except on the initial load after deployment, by utilizing cached data for faster subsequent page loads. When a graph is outdated by more than a day, a background job updates it, ensuring that users always see the most recent data. This improvement allows for quick access to Impact Graphs, even for large or old repositories like Rails, where the transition to git and GitHub resulted in a significant increase in attributed commits. This feature highlights how git efficiently preserves the authorship of contributions, as noted by Tom Preston-Werner.