As one of its announcements during the release of OS X Yosemite, Apple introduced a long-awaited update to the Mac Mini, which brings next-generation Intel Haswell processors along with an additional Thunderbolt connection and 802.11ac Wi-Fi connectivity to the small Mac. However, one development noted by Macminicolo is that if you plan on purchasing one of these new minis, you will not be able to upgrade its RAM.
Apple provides between 4GB to 8GB of RAM in its Mac Minis as default options, with configurable options of 16GB for all models. Even though the upgrade from 8GB to 16GB will cost an extra $200, and from 4GB to 16GB will cost $300 for the cheapest mini, the extra capacity will ultimately be worth it when you consider future OS upgrades, and software demands that will inevitably require more out of your system over time.