The iMac (Early 2009) computer has two SDRAM slots in the bottom of the computer and comes with at least 2 GB DDR3 SDRAM installed as 1GB DIMMs into each slot.
The maximum amount of RAM you can install in the computer is 8 GB (a 4 GB SO-DIMM in each slot).
You can use any Small-Outline dual inline memory modules (SO-DIMMS) that meets all of these criteria:
- 1066 MHz
- DDR3 SDRAM
You can use RAM module sizes of 1 GB, 2 GB or 4GB in each slot.
DIMMs with any of the following features are not supported in the iMac (Early 2009) computer:
- Registers or buffers
- EDO RAM
Always follow the upgrade instructions for memory installation as written. Never attempt to remove screws that are not listed in the upgrade instructions.
For more information about upgrading your iMac (Early 2009) memory, see iMac (Mid 2007) and later: Installing or replacing memory.