I use a HP Z-Book G3 Laptop with Thunderbolt3 Port and a Blackmagic Ultrastudio HD Mini, This gives you SIngle Channel Fill and Key. No extra power needed for the Ultrastudio HD Mini, power comes from the thunderbolt3 port. Its Plug and Play.
WIth the Z-Book I also use a AKITIO Thunderbolt PCIE BOX In there i have a Decklink Duo2. Works smooth with 2x Fill and Key with Caspar.
If you own already a good Apple Macbook, install Bootcamp, put windows on it. We run a system with a older Macbook with thunderbolt2 and a Sonnet PCIE Thunderbolt2 Chassis, also with an older Decklink Extreme.
SIngle channel FIll and Key with Caspar.