Can anyone out there point me in the direction of a 4K (3840 x 2160) HDMI switcher please, that actually works ? Tried several from Amazon, some quoting 4K, but none will pass 4K from each input. Just need 2 in, one out, to switch between a 4K PC (Alienware) and a 4K Satellite tuner, into a 4K TV. Tried several, as above, with various HDMI cables but no luck, so far. Many thanks.