Screen locks up after leaving redstone intensive area (both creative and survival) No Crash Log

Put the summary of the bug you're having here
Screen freezes and Minecraft client unresponsive when leaving an area full of "Lag Machines" (Pistons+Redstone Lamps hooked up to a very fast clock circuit)

What I expected to happen was...:
Describe what you thought should happen here
Nothing, should run fine.

What actually happened was...:
Describe what happened here
Minecraft crashes.

Steps to Reproduce:
1. Create a series of "Lag Machines" (i.e. pistons hooked up to hopper clocks, or and type of clock)
2. Log out in the middle of the machines.
3. Log back in.