Concept seems fun, incredibly laggy

I'm not sure if there was something wrong with my computer or something, but when I picked up this modpack to play (I was kind of excited about playing it) and created a new world it was incredibly laggy. Dangerous mobs spawn very commonly, and I was killed upon spawning in without time to react, partly due to low framerate. While I do appreciate the idea of community-made textures, I can't say I liked many of them. I eventually decided to play a different pack.

Overall, the concept seemed cool, but I think it'd be better for people who are fans of first-person shooters and have actual gaming PCs.