My iMac still has the original 2GB of RAM in the top two slots. Can I replace those top-slot RAMs with new 4GB RAM DIMMS at the same time I add two 4GB DIMMS to the now open bottom slots? Or can I only add the 8GB of new RAM to the bottom slots.
Thanks
iMac 27", macOS 10.13
Either of the above! You can add 2 modules to the empty slots or you can replace all 4 modules.
For reliable and comparable RAM upgrades, I will only purchase Mac modules from either OWC Mac sales.com or Crucial.com.
see > https://eshop.macsales.com/shop/memory/iMac/2011/DDR3_21.5_27
However this late in the game, I would hold back on investing a lot of money into that old of an iMac and only add 2 modules in the empty slots.
Either of the above! You can add 2 modules to the empty slots or you can replace all 4 modules.
For reliable and comparable RAM upgrades, I will only purchase Mac modules from either OWC Mac sales.com or Crucial.com.
see > https://eshop.macsales.com/shop/memory/iMac/2011/DDR3_21.5_27
However this late in the game, I would hold back on investing a lot of money into that old of an iMac and only add 2 modules in the empty slots.
You can use 4x4GB or 4x8GB modules.
If you are going to upgrade the RAM only use Crucial.com or Macsales.com RAM. Add 2x4 GB DIMMS is each of the empty slots or even better 2x8gb DIMMS. Upgrading to only 8gb is dumb.
Adding RAM to an iMAC Mid-2011-27"
