Performance optimization (improve efficiency / runtimes / memory usage)

Try to speed up the runtime of this library on large datasets. This can be done via:
- [ ] speeding up individual checks
- [ ] reusing more computation across checks
- [ ] using parallelism

This is a great issue to get started contributing to this repo! There are many ways to achieve speedup (speeding up individual checks will be the easiest). It is easy to verify speedup via basic benchmarking that also ensures the results remain the same.

Start by locating the individual checks and the code that runs them over large datasets. Establish basic benchmarks that verify both runtime and memory usage while confirming results remain unchanged. Done means a measured efficiency improvement, with benchmark results documenting the change.

Written by the indexing model from the issue text.