why babylon.js does not perform well on mobile devices fps 8-12? but sketchfub render fps 30-40.
hey!
well we will need for more detail 
They are so many reasons
- Difference in resolutions
- Differences in post processes
- etc…
So if you can provide a repro in the PG of your scene and the one in sketchfab we could help
in any scene even if the simple cube
Well I do not repro then
you will have to tell us more if you want us to help
Which mobile, what are the numbers, can you share a video…give us something