The iMac 27-inch (2020) solders its SSD but keeps a SATA bay open

The iMac 27-inch (2020) solders its internal SSD straight onto the logic board — no upgrading that after purchase. But Apple left a SATA connector and space for a 2.5-inch drive inside, so you can still add a second SSD or hard drive if you’re handy with a screwdriver.