It sounds to me that TVs or computer monitors are at 60/120/144 Hz, but I have seen TV 4k at 600 and 1200Hz of fluidity, How is that?
I am guessing you was looking at a Samsung TV and while it might say HZ on spec sheet, it really being calculated by Samsung CMR formula which uses
Frame Refresh Rate
Image Processor speed
to come up with the number.
So that 1200hz is calculated completely different then the number other tvs are using.