Caching WP Super Cache with different methods and load?

Question

caching

There is a low-cost server: pentium G3220, 4 GB of RAM, 120 SSD. To reduce the load on the server (sometimes there are freezes), I started using the WP Super Cache plugin on sites. There are essentially 2 options from which to choose a caching method:
- Use mod_rewrite to serve the cache.
- Use PHP to serve the cache. (Recommended).
Question: what is the difference between these methods and which one helps to reduce the load better?