The "iFixIt" site has "torn down" the new 21.5-inch iMac and says its scores a "very respectable" 7 out of 10 Repairability Score. Most of the disassembly is pretty straightforward and accomplished using a T10 Torx screwdriver and suction cups.
"A casual user can easily replace the RAM, and it's moderately difficult to access the hard drive and optical drive," says "iFixIt." "However, more adventurous users (those wanting to upgrade the CPU/GPU) will have to take out the logic board, which is a tricky process; they will also have to void the warranty if they replace the CPU. It's also quite difficult to reassemble the LCD and glass without a dust mite getting stuck in between the two."
You can find the completer teardown at http://www.ifixit.com/Teardown/iMac-Intel-21-5-Inch-EMC-2428-Teardown/54..., but highlights include:
° The LED display is manufactured by LG and is denoted by its model number LM215WF3. This is the same display used in the previous generation 21.5-inch iMac.
° Similar (but not exactly the same) to the Thunderbolt IC we found in the latest MacBook Pro 15-inch model, the iMac features the Intel L102IA84 EFL Thunderbolt port IC.
° The optional SSD appears to reside beneath the optical drive -- that's the only space "iFixIt" could find where something was clearly missing. There's three mounting points under the optical drive that have nothing attached to them in our machine, since this option is only available on 2.7 GHz 21.5-inch iMacs.
° If you want to remove the logic board, you have to snake it out from the rest of the iMac -- a combination of pulling up, as well as away from the casing. After a little bit of jiggling, it comes right out.
° In usual Apple fashion, one heat sink is reserved for the CPU, while the other oversees the GPU. And, in usual Apple fashion, you have to void the warranty in order to get a peep at the CPU processing power underneath.
° After popping off the CPU heat sink, "iFixIt" got a good look at the Core i5 processor. Their machine is powered by a quad-core 2.5 GHz Core i5-2800S CPU with 6MB of Intel Smart Cache.
° With a bit of magic, the GPU heat sink detaches from the logic board, exposing the AMD GPU board. You heard that right -- you don't have to replace the entire logic board if your GPU explodes from too much l33t gaming. You can just swap out the GPU board for another one.
° The main chips on the GPU board include the AMD Radeon HD 6750M GPU, as well as four Hynix H5GQ1H24AFR T2L 1 Gb GDDR SDRAM chips (totaling a cumulative 512 MB).
° Both the CPU and GPU on this machine have proper amounts of thermal paste applied, a happy departure from the gobs applied to the MacBook Pro "iFixIt" recently took apart.
° The big winner in the wireless communication area this time around is Atheros. At the heart of the Wi-Fi card is an Atheros AR9388-AL1A 802.11n wireless LAN chip.
° At the heart of the Bluetooth board lies a Broadcom BCM2046 Bluetooth IC, as well as 256 KB of SST 39VF200A CMOS Multi-Purpose Flash (MPF). We found this same Broadcom chip a long time ago in the first MacBook Air.
° Key players on the logic board include:
* 2.5 GHz quad-core Intel Core i5-2800S CPU with 6 MB of Intel Smart Cache.
* Intel BD82Z68 Platform Controller Hub
* Broadcom BCM57765B0KMLG Integrated Gigabit Ethernet and Memory Card Reader Controller
* Cirrus 4206BCNZ audio controller
* SMSC USX2061 (we believe this a USB 2.0 Hub Controller Family)
* Intersil ISL6364 CRZ Single-Phase Synchronous-Buck PWM voltage regulator for GPU core power applications
* Intel L102IA84 EFL Thunderbolt port IC
