why the fps mod i found here cap my fps to 30 instead of 60 ?

Did you use the right fps cap for the right game region?

ther is only one file in the dowload link, i'm using the italian version

Region shouldn't be a problem, the patch is universal for all region releases we know.

I've looked through possible solutions, and found 2 people with the same problem. One of them claimed it fixed itself when they redownloaded and coppied over the patch again. The other had weird one, apparently if you disable the sound in launcher's settings, the FPS gets halved. I've you disabled the sounds there, please re-enable. Hope it can gets fixed, good luck, and if it's still broken, please ask for help on Discord in #help_desk