Jay Bourgeois

Please! This is not a discussion forum.
"How bad is the lag"
"Small servers"
"a rather powerful PC"
"doubt you can run any server"
"just a few people"
"Noticing a lot of lag"
"big mob systems"
These are all subjective statements and in no way contribute to the resolution of this issue.
Comments should be objective, factual, to the point, and relevant to solving the issue.

Thanks.

I noticed this as well.
Steps to reproduce:

Create a redstone clock (my setup was repeater on 2 ticks, into a block with torch)
Hook sticky piston up to clock with block in front of piston
Walk 65 blocks to the side of the sticky piston.
move repeatedly between 64 and 65 blocks away from piston.
Observe the block in front of piston becomes duplicated (cosmetic only)
-------
attempts to mine the block reduces durability of tool.
no drops when mined.
placing any block ontop duplicated blocks replaces the duplicated block.

@Fienxjox thanks so much for your reply. I've been following this bug for a while, and very interested in seeing it through to resolution. Here is a link which I think narrows the problems down, at least somewhat. (http://www.mediafire.com/download/lz33a58qwmm0hut/SnapshotTest2.zip). The issue arises when a number of mobs must path-find (in this case a single long narrow path) and there are constant redstone (perhaps other types) updates.

As long as the burnout torch clock remains off the game behaves normally. If the clock is turned on the server load increases. I've also noticed, with the F3 screen their is an incredibly high number of allocations happening while the mobs are pathfinding.

While this might seem to be a contrived example, the same scenario might be found in a mob spawner. Having a large number of mobs preset with some redstone designed to kill the mobs. The same setup running in MC 1.8 produces no noticeable load on memory or cpu.