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?


Question: Android: How to Switch on Runnable in Message Queue?
Answer: 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!