@tylerhman '''yes''' it can. “For the 21.5-Inch "Mid-2017" iMac models, Apple reports that they have 8 GB of "2133 MHz DDR4" or "2400 MHz DDR4" memory onboard. However, in a pleasant surprise, as ++first discovered++ by site sponsor OWC, the memory actually is ''not onboard'' and can be replaced or upgraded after the initial purchase of the Mac, it's just unnecessarily complicated. Some models actually can support more RAM than Apple officially supports, as well.“ [https://everymac.com/systems/apple/imac/imac-aluminum-tapered-edge-faq/how-to-upgrade-imac-ram-aluminum-2012.html|from here] and the original OWC findings “We have confirmed compatibility of up to 32GB of memory.” [https://blog.macsales.com/41360-unboxing-teardown-of-2017-21-5-inch-imac-non-retina-model|right here]