You might not have noticed this, but if you go to upgrade your RAM to 8GB in your new iMac, you’re going to be paying a pretty penny. Now, it should be noted that 4GB DIMMS are very expensive already, so it’s certainly not all Apple markup. It seems a bit strange that they’d even offer it in a consumer system like this. Sure, if you can afford a new Mac Pro you can afford that $6100 memory upgrade, but who’s getting an iMac and willing to drop an extra grand on memory?
The problem is just that the iMac’s board only has room for 2 DIMMs. 4GB DDR3 1066MHz costs at least a couple hundy a stick. If Apple had allowed iMacs the space to have 4 DIMMs, they could sell 4x2GB DIMMs instead of 2x4GB, saving probably around $700. Evidently they weren’t interested.
[Thanks to the people at Reddit for pointing this out]