Is there a way to specifiy which objects are tesselated or not?

I was planning to create a game that uses a lot of basic geometric shapes. I would like for round objects like cylinders, cones, spheres, etc. to be perfectly round
Sort of like this in this viideo:

Quest (1985)
:

http://oi65.tinypic.com/e84vfc.jpg

but I realize having such high poly models could be expensive (performance-wise) especially with so many reflections. I looked up of a way to remedy this, and found that tessellation can be used to smooth out edges, but at the same time I would like for some of the objects to have harder edges, and I don’t want the tessellation to change the shape too much.

This is a video with examples where tessellation affects the shape of gems:

In case you’re wondering, the video card I have is an AMD RX460 (4GB GDDR5). When I release my game: I would like for people to play it with a card with the similar specs. I don’t want the consumer to have to buy an expensive high end graphics card just to be able to run my game (I want it to be accessible), so I want to optimize it.

Do you think I can create a scene like in the short film and have it run smoothly? Do you think it would be better to just create high poly models or to use or will tessellation have better performance? If tessellation would be better, is there a way to specify which objects will be tessellated?

Thanks in advance.

You have to specify the tessellation in materials. So you can have different materials for tessellated objects and different for Non tessellated objects.

Select your material in material editor and in the details panel search for “Tessellation” and change the mode from “No Tessellation” to “PN Triangles”

Okay, thanks!