A third-party reseller, Expercom, has published what it says are the extra build-to-order costs for the 2012 iMac, which starts shipping on Friday. The base 21.5-inch system has just a single, $200 option for upgrading from 8 to 16GB of RAM. Moving to the high end, though, also allows a $200 boost to a 3.1GHz Core i7 processor, and a $250 upgrade to a Fusion Drive, Apple's hybrid SSD/HDD format.
