When i enable raytracing and restart then it freeze my pc

I’ve seen from other questions that i’m not the only one with this problem. Unfortunatly i’ve not still found a solution.
I’ve a gtx 1080TI, a 7i core. I’m working on a project for my school and i’ve to compose a showreel on UE4.
I enable ray tracing, on project setting and restart.
When i open it get stuck to 45% untill it freeze the pc entirelly. (It happen also when i build lights).
I’ve no idea what to do.