I placed 620 sparks on our server.
When I looking to them, there is only 3 fps
(http://imgur.com/8FC9ays)

But if I looking to other places, there is 63 fps

Could you add a config for disable sparks' animation?

This repository is no longer maintened.
Sparks are entities, placing many of them in one area and then complaining about performance drop is user fault.
Disable Terrain animations via Optfine if it's that important.

It can be improved, but only with a Forge change (that would only be in 1.10.2)
For now disable terrain animations

The sparks use a normal atlas sprite, the animation cannot be disabled (without Optifine) unless you use a resource pack to change the spark texture to not be animated