5 - 20 minuten
Last year I upgraded the memory on my iMac 20" Mid 2007 from 1GB to 4GB using Crucial Memory. There was a handy software tool to order just the RAM the iMac required. This year I wanted to upgrade the CPU. GPU, and hard drive. I replaced the Intel Core 2 Duo T7300 (2.0 GHz, 4 MB L2 cache, Merom core) with the Intel Core 2 Extreme X9000 (2.8GHz, 4 MB L2 cache, Merom core). I replaced the ATI Radeon HD 2400 XT (128 MB) with the ATI Radeon HD 2600 Pro (256 MB). Also, I replaced the 250 GB HDD with a Crucial m4 128 GB SSD, because most of my data is stored on external hard drives. I upgraded the iMac, because at five years old it needed the fix!
Very well. I mainly followed the guide for installing a heat sink here: iMac Intel 20" EMC 2133 and 2210 Heat Sink Replacement. I also used the guide for using Arctic Silver Thermal Paste. I took my time; overall, it took 6 hours from start to finish. Then...I formatted my SSD, reinstalled OSX Mountain Lion 10.8.2, and restored a recent Time Machine backup.
Read about your old components and new ones. Make sure everything will be compatible.
Read guides on iFixit. Read other person's stories on iFixit and other message boards. Once I read many stories, I realized I was not alone and should not be scared to try this myself!
Take your time during the disassembly and reassembly of your machine.
Take breaks. :-)
When taking out the Torx screws, I placed them on a sheet of paper and labelled the various sizes. This allowed me to keep track of the screws and to easily identify them.