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Background and Identification
The Acer Aspire brand has been applied to desktops, laptops, and all-in-one solutions for many years, but the E5 series was first released in 2015, and includes 15" and up desktop replacement laptops. They include a large screen, a dedicated graphics card as well as more RAM than most laptops.
To identify the E5-721-64T8 model, your laptop should have a sticker on the bottom, including a barcode and, directly above it, the model number. Additionally, this model is one of the few to lack an optical disk drive, so, if the laptop measurements match the specs and does not have an optical drive, this is probably the model you have.