The Shield tablet is constrained by TDP requirements and lack of software. You can bet it's GPU won't get anywhere near 360 GFLOPs in a real world situation since it's widely known that these mobile hardware throttle clocks down quite agressively when being pushed, also, nVidia's specifications usually are made based on a perfect scenario, tablets don't have active cooling, so, yeah, performance is bound to be a lot lower. Also, being ran on Android, you can expect no game to take any advantage of the hardware, but it'll surely play existing games a lot better than other Android hardware out there, so at least you can have that if Android gaming is your thing.