Earlier quoted context omitted.
I have tests which verify DNA analysis. The test data vectors are large -- a few hundred MB here, a couple GB there. The hundreds of tests that use these test vectors still run in a few seconds. If you're using a tape drive or SD cards, sure. But even a 10 year old 5400RPM on an IDE connection should be able to satisfy your tests' requirements in a few seconds or less. I suspect your tests are just as monolithic as y…
Sounds like you have tests that need to read (probably cached) data files while the parent poster has tests that need to write to disks (probably in a database transaction). Those are different enough that run times won't ever be comparable.
If you need to access a database in your tests you're probably doing it wrong. Build a mock-up of your database accessor API to provide static data, or build a local database dedicated for testing.