This means that Apple needed to rearrange the components to fit the larger RAM modules inside the iMac Pro’s chassis. While “mobile” size SO-DIMMs with ECC exist, early marketing images from Apple indicate that the company is instead using full-size DIMMs in the iMac Pro. This is crucial for the reliability of mission critical applications and databases, although its benefits likely won’t be noticed by most prospective iMac Pro buyers who are primarily interested in the system’s computational and graphical capabilities. Unlike the “standard” iMac, the iMac Pro uses error-correcting code (ECC) memory, which helps counter any errors or corruption that may occur while data is stored in memory. The upcoming iMac Pro, set for release this December, is an entirely different beast. Check out Apple’s instructions for details.
It was therefore not surprising to see our friends at Other World Computing quickly confirm that the entry-level iMac does indeed support the full 64GB of RAM. This was odd, as all three iMacs utilize the same chipset and processor platform. As mentioned above, only the mid- and high-end 27-inch iMacs support 64GB of RAM, with Apple taking the time to clarify that the entry-level 27-inch model is limited to 32GB.Sure, the new iMacs use faster DDR4 memory, but many applications value the quantity of RAM over the speed, at least to a certain degree. So if you’ve got a 2015 iMac and are considering the 2017 upgrade for the increased RAM limit, you may want to try a RAM upgrade instead. While it’s good to see Apple raise the “official” limit, the previous 2015 27-inch iMac also supported 64GB of RAM just fine, even though Apple’s official limit was only 32GB. Apple noted during the iMac section of the keynote that its mid- and high-end 2017 27-inch iMac models now support a maximum of 64GB of RAM.So here’s a quick rundown of what we know so far when it comes to system memory on these new iMacs. Keeping with this awkward tradition, the RAM situation for Apple’s new iMacs is still just as confusing.