Organics includes several quality texture packs for different purposes, but this one is designed to enhance realism with completely new textures. The Modern and Realistic pack exists so that miners can see the beautiful nature, the picturesque sky and the right blocks without using shaders. If you think that such texture packs are not suitable for weak computers then you are wrong.
Modern and Realistic Textures work well on older PCs, although freezes are possible. For today it is one of the best realistic packs with a 32x resolution for Minecraft 1.12.