Installing 12GB ram on new iMac

[Loono]

Hi, I decided to buy 2x4GB ram from Crucial as prices have dropped alot recently. This will mean that I will have 12GB ram in total (2X2GB stock ram).

I have the new current model imac with 4 memory slots. I have heard that it is marginly better to have matched memory size.

I am wondering whether all 4 slots (quad) have to be the same size for this small benefit or it is dual slots i.e. left memory bay is independant to the right memory bay?
Also to note: by default, Apple put the 2x2GB sticks horizontally (one in the top left memory bay and one in the top right).

So all in all,

Is it better for me to install:

2X2GB ram on the left memory bay + 2X4GB ram on the right memory bay

OR

Apple's way (leaving the 2x2GB alone and just install the 2x4GB in the spare slots)

1x2GB (top left memory slot) + 1x2GB (top right memory slot)
1x4GB (bottom left memory slot) + 1x4GB (bottom right memory slot)

Does it matter?

 

[mulo]

as you have the i3 you only have dual channel memory, this means "matching paris" is only two, so you can do that just fine.
if you had the i7 it would be a different story