GerryB
You might run into trouble with the USB version of the Intensity Shuttle, only selective hardware/chipsets will work with this one, i use the Thunderbolt 2 version on my MacBook Pro (early 2015 13" 8GBram)
better convert from that one, or....... why do you choose the Intensity Shuttle ? since you are "only" using HDMI .... you want to use the analog inputs/outputs also ?
Check for other devices, also some devices wil not go as high 1080p60, check this when looking for a capture device, when this is needed.