Teardown of Apple's 21.5-inch Thunderbolt iMac finds removable graphics board

iFixit posted the results of their iMac teardown on Wednesday, offering a peek inside Apple's new all-in-one desktop. The model they dissected includes an AMD Radeon HD 6750M GPU paired with four Hynix GDDR SDRAM chips.

"With a bit of magic, the GPU heat sink detaches from the logic board, exposing the AMD GPU board," the solutions provider said. "You heard that right, folks — 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."

iFixit also noted that the CPU and GPU on the machine they looked at had proper amounts of thermal paste applied. That's a change from the new Thunderbolt-equipped MacBook Pro they looked at in February, which had excess thermal paste on both the CPU and GPU that could lead to overheating issues.

The new iMac also features a controller chip for its high-speed Thunderbolt input/output port that is similar, but not exactly the same, as the one found in the MacBook Pro. The iMac sports an Intel L102IA84 EFL Thunderbolt port IC.

Though the model looked at by iFixit did not include the optional SSD boot drive, they concluded that it would reside beneath the system's optical drive, as that was the only space where "something was clearly missing." There are three mounting points under the optical drive that have nothing attached to them in the model powered by a 2.5GHz Intel Core i5 quad-core Sandy Bridge processor.

Other highlights from the teardown:

• 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" iMac.

• The Wi-Fi card is powered by an Atheros AR9388-AL1A 802.11n wireless LAN chip.
• Bluetooth is served up via a Broadcom BCM2046 Bluetooth IC, and the card also includes 256 KB of SST 39VF200A CMOS Multi-Purpose Flash (MPF). That same Broadcom chip was found on the very first MacBook Air.
• The new iMac was given a score of 7 out of 10 on the company's repairability score.

For more, see the complete teardown, with additional images and details, at iFixit.