Strix Halo can only allocate 96GB RAM to the GPU. So GPT-OSS 120B can be ran only at Q6 at best (but activations would need to be partially stored in the CPU mem then).
I bet you're confusing VRAM (the old fixed thing) and GTT (dynamic) memory allocation. Linux amdgpu does GTT just fine. amdgpu_top is an example monitoring app that shows them separately.
