iFixit has already disassembled the new iMacs that were released yesterday. The teardown didn't reveal too many changes from the previous version, though there are a few new features worth mentioning.
Both the 21.5-inch and 27-inch models
include the new 802.11ac wireless standard, while the 27-inch model includes the new PCIe-based
flash storage that was originally introduced in the MacBook Air back in June.
The 21.5-inch model has a few differences from its larger sibling,
according to iFixit. It now includes a new empty PCIe SSD slot so users can upgrade the base model iMac to the Fusion Drive
combination HDD/SDD drive that Apple introduced last year. In last
year's 21.5-inch model, Apple did not include an empty PCIe slot on the
logic board.
More disappointing, for users who like to upgrade their machines, is the
fact that the CPU is soldered directly to the logic board, making an
upgrade nearly impossible. iFixit gave the 21.5-inch model a
2 out of 10 for repairability, largely because of the soldered processor.
The 27-inch model received a
5 out of 10.
The largest issue with upgrading the iMac is getting the glass and LCD
panel out of the machine, making repairs impossible for all but the most
determined do-it-yourselfers.