razer blade 15 2018 poor performance ac syndicate

Hi,
I'm really struggling getting AC Syndicate to run more or less smoothly on my blade 15. My Blade has the 1070 max q, 16 gb ram, i7, 1tb ssd. Even on lowest settings the game has huge framerate drops, with complete freezes. In task manager the 3D graph is at 100% whereas only about 4gb of the GPU are being used.
The problem can't be with the specs of my machine, I think. Might there be some setting wrong? Or is the game just broken?
I do not know whether this is related or not, but in windows settings my vram is only at 128mb.
Any help would be greatly appreciated!
thanks a lot