4X 512MB RAM Memory 4 IBM Lenovo ThinkPad R51 Notebook Series DDR1-PC2700 A49 | eBay
Meet this bad boy from 2006, IBM ThinkPad R51 with Celeron M and 256 MB of RAM. Still works fine and is in good enough condition considering it being 14 years old.
1GB (1X1GB) RAM Memory 4 IBM Lenovo ThinkPad R51 Notebook Series DDR1-PC2700 | eBay
parts-quick 2GB (2x1GB) Compatible Memory for IBM ThinkPad R51 1830-xxx PC2700 333MHz SO-DIMM Notebook RAM Brand at Amazon.com
IBM ThinkPad R51 15" Laptop, 1.6GHz Pentium M CPU, 512MB RAM, 30GB HDD, Win XP | eBay
linux - Started this machine for the first time after 18 years!! IBM R51 (32 bit single core Pentium M), 1gb RAM, 40gb old mec - devRant