OWC 8 GB (2 X 4GB) ram PC8500 DDR3 1066MHz sodimm 204-pin Memory Upgrade Kit, (OWC8566DDR3S8GP), Compatible with MacBook Pro, MacBook, Mac Mini and iMac at Amazon.com
PC3-8500 4 GB RAM Chip
RAM : 4GB vs 8GB vs 16GB Test in 8 Games - YouTube
What's the physical difference between 4 GB RAM and 8 GB RAM? What are they made of? How does it work? - Quora
memory - Would there be any problems if I install an 8GB RAM stick to my desktop computer which has 4GB RAM installed? - Super User