My conclusion from using the debugger and inspecting the elements is that you cannot determine in handleMessage() whether a message or a runnable is being processed.

I found empirically (through elimination) that all my Runnables had a msg.what == 0 when I set all my messages to have msg.what to be something other than 0.  Use with care!

Android: How to Switch on Runnable in Message Queue?
I've been told it is important to use matching DIMMs when installing memory to take advantage of the 128 bit throughput. I'm looking to buy a new 27" iMac (mid 2011) which has 4 memory slots. If I put matching 2x2GB in 2 of the slots and matching 2x4GB in the other two slots, will that reduce its throughput or cause any problems? 

Do all 4 have to match or do each set of 2 need to match?
