40-series water blocks can even be single slot: https://shop.alphacool.com/en/shop/gpu-water-cooling/nvidia/13869-alphacool-es-geforce-rtx-4090-reference-1-slot

40-series water blocks can even be single slot: https://shop.alphacool.com/en/shop/gpu-water-cooling/nvidia/13869-alphacool-es-geforce-rtx-4090-reference-1-slot-design https://shop.alphacool.com/en/shop/gpu-water-cooling/nvidia/...