Hallo Michel,
sorry, wrote these letters very late and weary.
Yes the Macbook does have a SSD.
I use the latest official Izzy Version 2.0.5 with 2.x upgrade license.
I don't do nothing to the files but playing it with standard values in the Movie Player (speed 1).
I tried different settings with the framerates. Content 25, Izzy 25; Content 25, Izzy 50; Content 50, Izzy 50.
Nearly no difference...
I found a solution now. Used PhotoJPG as Codec. Now it is very fluid with any settings!
Best
Delil