With a few inexpensive upgrades (ram and SSD), this early 2009 mac mini runs Mojave surprisingly well : r/mac
How To: Mac Mini RAM Upgrade, Pictures Inside! | MacRumors Forums
CMS 8GB (2X4GB) DDR3 8500 1066MHZ Non ECC SODIMM Memory Ram Upgrade Compatible with Apple® Mac Mini Core 2 Duo 2.26 (Late 2009) - A35 at Amazon.com
Upgrade or repair 2009 Mac Mini to SSD, 8GB RAM - YouTube
How to Install Memory (RAM) in a 2009 Mac mini (Macmini3,1) - YouTube
Mac mini Model A1283 RAM Replacement - iFixit Repair Guide
OFFTEK 1GB Replacement Memory RAM Upgrade for Apple Mac Mini 2.0GHz Intel Core 2 Duo (DDR3) (MB463LL/A - Early 2009) (DDR3-8500) Desktop Memory at Amazon.com
Mac mini Model A1283 RAM Replacement - iFixit Repair Guide
Mac mini Model A1283 RAM Replacement - iFixit Repair Guide
CONFIRMED! OWC supports 8.0GB memory in Mac mini 3,1 machines
8GB (4GBx2) Team High Performance Memory RAM Upgrade For Mac mini “Core 2 Duo” 2.26 (Late 1 2009) MC238LL/A Macmini 3,1. The Memory Kit comes with Life Time Warranty. at Amazon.com
8GB -2x4GB Memory Ram Upgrade Apple Mac Mini-3.1 Late 2009 2.26GHz MC238LL/A | eBay
Memory Upgrades for 2009-2010 Mac mini Unibody Models
A-Tech for Apple 8GB Kit (2X 4GB) DDR3 1067MHz / 1066MHz PC3-8500 SODIMM MacBook, MacBook Pro, iMac, Mac Mini (Late 2008 Early/Mid/Late 2009 Mid 2010) Memory RAM at Amazon.com
Timetec 8GB KIT(2x4GB) Compatible for Apple DDR3 1067MHz / 1066MHz PC3-8500 CL7 for Mac Book,
OWC 6GB (2GB + 4GB) PC8500 DDR3 1066MHz SO-DIMMs Memory Compatible with Late 2008, Early 2009, Early 2010 MacBook, MacBook Pro Unibody Models, 2009/2010 Mac Mini, 2009 iMac Models at Amazon.com
Upgrade or install memory in your Mac mini - Apple Support
Success! Big Sur install with OCLP on Mac mini 2009 3,1 with 6GB of ram and SSD. Running okay but does slow down with a few windows open. Recommended to upgrade to
CMS 8GB (2X4GB) DDR3 8500 1066MHZ Non ECC SODIMM Memory Ram Upgrade Compatible with Apple® Mac Mini Core 2 Duo 2.26 (Late 2009) - A35 at Amazon.com
A-Tech for Apple 4GB Kit (2X 2GB) DDR3 1067MHz / 1066MHz PC3-8500 SODIMM Memory RAM Upgrade for MacBook, MacBook Pro, iMac, Mac Mini - (Late 2008, Early 2009, Mid 2009, Late 2009,
