Apogee Jam + MacBook Pro latency

[gotw42]

I am using the 10 day trial of AmpliTube 4 with my Apogee Jam and 2015 MacBook Pro. The rig I'm using is the basic one that is loaded when launch the app. Using a buffer of 256 the latency about half a second, unusable. From 128 down to 16 it is still noticeable and not very fun. The CPU monitor is very low while playing so I don't think that's the problem. Does anyone have any ideas for diagnosing the culprit or how to improve the latency?