The idea is to make an endless, possibly randomised,terrain for the player to explore (Modified from a concept found on Blendswap). Right now, I have it set up so that as the player walks toward the edge of a piece of land, then a new piece will spawn in front of them. This works fine. The only problem is there is a huge drop in framerate whenever the player walks onto a spawned landmass, and this is a big problem. Any ideas why this could be? I've included some screencaps with the fps breakdown. Let me know if there is more info I can give that might be helpful. Thanks!

Frame rate screenshots on original and spawned landmasses