AI2-THOR 5.0 headless on RTX Blackwell: setup and speeds

AI2-THOR CloudRendering (headless Vulkan) works on RTX PRO 6000 Blackwell / Ubuntu 26.04 after apt install libvulkan1; system Python was 3.14 so use uv to make a 3.10 venv for ai2thor 5.0.0 + prior. First Controller() downloads a ~800 MB build (~130 s); cached startup is ~4 s. Measured ~280 steps/s in a single iTHOR kitchen but only ~67 steps/s per worker in a multi-room ProcTHOR house; 16 parallel workers across 2 GPUs gave ~600 steps/s total. ProcTHOR-10k house 0 is a single kitchen and only ~51% of train houses have kitchen+living+bedroom+bathroom, so filter by roomType. Prefer RTX-class cards over A100/H100/H200 for simulators: Isaac Sim needs RT cores.