How to create clean displacement edges without crazy amounts of subdivisions?

I’m trying to create something similar to what is being done in this video: https://www.youtube.com/watch?v=068g41cTrYY&t=228s

I’ve been able to create something that looks similar to this but only if I turn on experimental features, adaptive subsurface (to improve performance) and then turn up the number of subdivisions to a very high amount (4-5) for it to not look all ragged (this takes minutes to update and is unworkable). It seems in Octane this is pretty straightforward but I’d much prefer to use Cycles.

Is there some way to do this efficiently in Cycles?

Maybe some way to align the map with the available subsurface or force it to only lift up complete squares or perhaps limiting the number of input colors to the displacement… I don’t know… surely theres an easier way to achieve this.

edit: This seems promising: https://www.youtube.com/watch?v=VY9vHdwUo98

So what you did was described in the first video. This fits the geometry so that the geometry that is closer is higher resolved. But it’s clear that this concept quickly overtaxes even the best hardware. If the limits of the geometry are outside the camera limits, like in the second video, a normal map is sufficient.

You can blur the image to soften the edges which will help.

You can add a smooth modifier after displace

You can create a simple base topology (instead of a plane) that matches the primary form of the map, this will only work for certain types of images.

You can use high subdiv levels, apply it, and then decimate or other auto retopo, and then clean up.

What I ended up doing is very much like what Photox suggested.

The mesh I wanted to apply this to was too messy and you need to UV map everything per quad so I shrinkwrapped a plane to the surface I wanted this effect on and UV unwrapped and edited the map carefully like in the video. After adding 2 subsurfs the detail was good enough but unwieldy. To my surprise greatly reducing the polys with decimate still retained most of the detail.