I tested the new snapshot today and I have strong differences between the Snapshot Version and the 1.7.5/1.79 with the Frames per Seconds and Chunk Loading.

Minecraft 1.7.5 - Up to 30/200 FPS
Minecraft 1.7.9 Up to 30/200 FPS (both without mods)
With the Optifine Mod I'm gaining even more FPS (lowest: 25, max: 250)

Snapshot Version: Between 1 and 8 FPS.(I already tested the 14W27a and the 14w29b and it's decreased highly from my normal standard.

I hope you handle the resources as well for all Clients without a high qualified Gaming PC or something like this.