iFixit: Thunderbolt iMac Includes Replaceable GPU

With Apple’s new Thunderbolt-equipped iMac available for less than a day, the iFixit team has already stripped the computer down to its frame. Inside they found Intel’s quad-core Core i5 processor, along with a removable graphics processor board.

“With a bit of magic, the GPU heat sink detaches from the logic board, exposing the AMD GPU board,” iFixit’s Miroslav Djuric 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.”

Replacing the GPU, however, comes at a cost since digging that deep into an iMac will void the warranty.

iMac teardownApple’s iMac, now in pieces

The display in the new iMac comes from LG, just like the model it replaces, and the Thunderbolt controller chip is similar to what Apple included in the MacBook Pro — the computer that Apple used to introduce the new interface port.

Thunderbolt is the new port found on the MacBook Pro and now the iMac. It uses the same connector as Mini DisplayPort, offers dual-channel 10Gbps data transfer, and supports video, audio and other data through a single connector. In its current form, Thunderbolt supports up to six devices in a single chain.

The new iMac is available with a solid state drive as a build-to-order option, and based on mounting points iFixit found during the teardown it appears that the drive attaches underneath the optical drive.

Apple apparently has a better system for applying the thermal paste that attaches the heat sinks to the CPU and GPU. That’s good news, since applying too much, which is what they found when disassembling the latest MacBook Pro, can lead to overheating issues.

The iFixit team also found Broadcom chips for Gigabit Ethernet and the Memory Card Reader Controller, an audio controller from Cirrus, and Intel’s BD82Z68 Platform Controller Hub. The company also confirmed that RAM is user upgradable, just like previous iMac models.

The full teardown with additional photos is available at the iFixit Web site.