iFixit has already disassembled the new iMacs that were released yesterday



From MacRumors:

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.

  iFixit Tears Down New iMacs, Finds Soldered CPU on 21.5" Model