Apple Mac mini (Mid 2011) - Manual (Page 40)

40 Chapter 3 Boost Your Memory
Your Mac mini came with at least 2 gigabytes (GB) of memory on a pair of 1 GB
memory modules. You can replace these with a pair of 2 GB or 4 GB memory modules,
for a maximum of 8 GB of memory.
The following pages show you how to install memory modules in your Mac mini.
WARNING: Apple recommends that you have an Apple-certified technician install
memory. To arrange for installation, contact an Apple Authorized Service Provider
or an Apple Retail Store. Damage you cause to your equipment while installing
memory isn’t covered by the limited warranty on your Mac mini.