Sorry, I have 10.5.2 Kalyway.

EFI string? Not sure how to do that.

But the nvidia installer has an option for EFI Studio. Anyhow I think it appears from other posts that the installer does that efi string for me. I guess I will try and see.

After I update to 10.5.5 using Combo Updater from Apple.

THank you!