I would like to upgrade the RAM from 4GB to 8GB on my iMac 21.5" 2011. The current RAM modules are two 2GB ones. What are the available options to upgrade the RAM?
1) Get a 4GB RAM
2) Get two 2GB RAMs
On the Apple website: http://support.apple.com/kb/HT1423
For the iMac (Mid 2010) and iMac (Mid 2011) models, use 2 GB or 4 GB RAM SO-DIMMs of 1333 MHz DDR3 SDRAM in each slot.
I didnt get it whether we need to fit the same capacity RAM modules in...