How to test correctly?

Question

Software testing

Hello.
2 abstract hypervisors are tested for performance. One of them has write caching, the other does not. Naturally, enabling caching increases write performance by an order of magnitude.
Question - how to test correctly, with or without caching?

Answer 1

Should the cache be tested or not?
If yes, then both tests should be performed.
If not, then if in production it works with the cache, then with the cache.