While you will not have the benefit of the matched pair, your total memory at 6GB is higher, negating the boost you get from the matched pairing at 4GB. The maximum memory you can install in these machines by way of a matched pair is 4GB (2GBx2.) However, the actual maximum memory in this machine is 6GB, which is installed with a single 4GB and a single 2GB. One common example is the iMac Model ID 7,1 or iMac 8,1. In many cases, however, it is necessary to consider the difference between adding a single DIMM that increases your total memory versus having a matched pair. 4GB Paired vs 6GB Non-Paired Configuration For example, a pair of 2GB modules (4GB total memory) will perform better than a single 4GB module.
When people talk about a 'matched pair' performing better, they are talking about very specific cases of two modules of the same size when compared to an individual module of the same size. With the exception of Apple RAM for the Mac Pro Model IDs 1,1 and 2,1 and the Mac Pro 3,1, no other Mac requires memory to be installed in a matched pair. Often we have customers asking if they should install Apple memory as a matched pair or not.
