Hello,
I have a 2019, 27" iMac. I have purchased four 16GB DDR Ram. When I insert them all the mac refuses to boot.
However, if I remove two of the ram and insert the original 4GB RAM then the mac boots and I can see two 16GB and two 4 GB in the slots.
Whta is the issue with adding 4 x 16GB Ram modules?
There are many types of RAM. "DDR" in and of itself is not a complete description, and does not tell us whether you have RAM that is compatible with that iMac.
Install memory in an iMac - Apple Support says that you can install up to 64GB (4 x 16GB DIMMs).
iMac (Retina 5K, 27-inch, 2019)
Use Small Outline Dual Inline Memory Modules (SO-DIMM) that meet all of these criteria:
According to MacTracker, that Mac has an official RAM limit of 64 GB, and an actual one of 128 GB.
Macs can be picky about RAM – so most people here would recommend purchasing RAM either from Crucial or from Other World Computing (MacSales), and using the tools on those sites to find the RAM that those vendors specifically recommend, and guarantee to work on, your system.
There are many types of RAM. "DDR" in and of itself is not a complete description, and does not tell us whether you have RAM that is compatible with that iMac.
Install memory in an iMac - Apple Support says that you can install up to 64GB (4 x 16GB DIMMs).
iMac (Retina 5K, 27-inch, 2019)
Use Small Outline Dual Inline Memory Modules (SO-DIMM) that meet all of these criteria:
According to MacTracker, that Mac has an official RAM limit of 64 GB, and an actual one of 128 GB.
Macs can be picky about RAM – so most people here would recommend purchasing RAM either from Crucial or from Other World Computing (MacSales), and using the tools on those sites to find the RAM that those vendors specifically recommend, and guarantee to work on, your system.
Contact Mr Memory for help with replacements or a return and refund.
Your options at this point seem to be,
1) return two of the modules for a refund and run with 40GB
2) return all 4 modules for a refund and purchase from a different vendor
What RAM modules did you purchased...?
(please provide the supplier and part number or a link to the web page)
DDR Memory update issue
