try this to fix the problem, has to do with SP1 for vs2010 if you have that setup FIX: The IntelliSense feature in SSMS 2008 R2 may stop working after you install Visual Studio 2010 SP1

Does SQL Server 2008 R2 Express have Intellisense?
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?
