In case you would have reflective surfaces, HDcache set up to take care of glossy reflections (reflection threshold at default) , and you had some flickering that positional sensitivity would not resolve.
Unfortunately I can't really understood what this settings do (Positional/directional sensivity). In online interactive help they described as is. But as I've tested Positional sensivity set to 100 resovled flickering in this case. May be some flickering was left, but I can't see it in animation so I think it's no matter.
You need to check the values of Level and glossiness both for reflection and for the refraction (1 to 0.89/0.98)
HD Chace
Position sensitivity 100 does not help anything!
Max Record 99999 - vanishes (default is ok or values between 300 and 2500 - always depends on the circumstances )
A touch of Ray Tracing 28/32
I took an example from your slot material "Corona Glass win"
the yellow arrow indicates that the material you produce more or less noise (from personal experience)
Sorry, but I didn't undersrtood what do You mean
A touch of Ray Tracing 28/32 .
Glossiness from 1 to 0.89/0.98 is a good idea and I'll try to check this in near future.
Position sensivity 100 is not Holy Grail of course, but it really helps me to produce flicker free render with lower rendertimes in this case.
Max Record 9999 is recommended setting by online documentation. Why and what this means - I don't know :(
Final animation is rendering and after some post I'll share it in gallery. I've chacked it in progress and it seems that the flickering is gone.