Lag in the vanilla overworld is OK, not bad. Lag in any of the other dimensions, however, is completely unplayable. OreSpawn has 6 alternate dimensions. Somehow, this problem affects 5 out of the 6 even though all use nearly identical code. The Chaos Dimension is the worse by far, as it contains a lot of sky space (it is really in inverse nether world, a series of connected islands). The crystal dimension is the least affected, but it uses all its own block types instead of the standard stone and dirt and grass and such.

I've put printfs at the top and bottom of provideChunk() and populate(), and the problem is not there. The lag hangs occur outside of these routines. I even completely commented out the populate() code, with no effect. Unfortunately Forge no longer supplies compileable MC code with their build, so I am not able to investigate this problem further.

To reproduce the problem, either run the OreSpawn mod and change dimension by right-clicking an ant with an empty hand, or make your own dimension based off the vanilla world and register it through Forge. I will be happy to help, supply code, and even test fixes if you would like me to.

My initial guess would be, that the original setBlock() lag problem of 1.7.2, was somehow migrated into chunk loading. Maybe all the lighting logic moved? Browsing through the code it would seem to appear that way. If there is even a cheap-and-dirty fix, I'm game... the OreSpawn fans are whining at me to release this thing...

If you need anything from me, please just let me know. I would be more than happy to help!