Suggestions for optimizing a voxel terrain?

Hello! I’ve been trying to build a voxel terrain system on Unreal Engine 4, but I’m getting an unacceptably low frame rate with a very low block count. I’m using procedural mesh components for chunk rendering, which is the less expensive solution I could find (attachment 1). As you can see (attachment 2), I’m not rendering hidden block faces, nor the inner side of the geometry. The faces also have no collision nor UVs.

I know that an ideal voxel terrain would benefit from other culling methods such as frustrum culling, but at this point, you can already tell that there’s something very wrong with it. I used the exact same technique to build this voxel terrain (attachment 3) using LWJGL, and I got over 600 FPS with more than 3 million blocks on the scene. Of course OpenGL and Unreal are incomparable, but it’s not normal to get these performance results only by rendering a geometry that probably has a lower polycount than the default skysphere.

Sooo… Some help, please? Thanks in advance!