Apple’s new 5K iMac, which was announced and made available to purchase on Tuesday, is its first all-in-one to support up to 64GB of RAM, new tests have confirmed. Until now, only the Mac Pro was capable of packing so much memory.

You cannot buy a new iMac with 64GB of RAM; Apple’s maximum offering right now is just 32GB. However, third-party component manufacturer Other World Computing has already installed a 64GB RAM kit in the new 5K iMac and confirmed that it works perfectly.

OWC is set to begin selling its RAM kits for the new iMac this week. It will offer 16GB modules in either 32GB or 64GB configurations for $599 and $1,195 respectively, plus a single 16GB module for $329.99, and a 48GB kit consisting of two 16GB modules and two 8GB modules for $729.

Unfortunately, Apple has soldered the RAM into the new 4K iMac, so it’s impossible to upgrade it. With that being the case, those planning to buy this model will need to ensure they get plenty of RAM when placing their order. The maximum available right now, however, is just 16GB.