By default, OpenCore normally knows what's best for your Mac. These settings are probably already set correctly, but we want to skim over them to double check.

In extras, you'll see a bunch of NVRAM options. You'll probably leave most of this untouched.

Now, you will see "APFS Trim." If you are running a Mac that supports macOS High Sierra natively, your Mac will run APFS with or without this checked. If you are installing an older version of macOS (check out Guide #4 Continued), and you do not want to use APFS, uncheck this. If your Mac has a hard disk and NOT a Solid State drive, uncheck this.

In the end, I have always kept this checked, as I have never had an issue with it activated. If you have a faulty Solid State drive, then you should definitely uncheck this.

If you're left confused... just leave it be.

TRIM support is simply a program that makes reading and writing faster on a Solid States Drive. If your SSD is faulty, TRIM support may worsen performance.