All MacBooks with plastic enclosures take the same RAM type. The only differences are the maximum amounts you can install. Earlier models had a maximum amount of 3GB, but were later on increased to 4GB. The differences are in the Intel Chipsets.

MacBooks with aluminum enclosures now take PC3-8500 DDR3 RAM. The maximum amount of RAM is the same as the previous model at 4GB.

In early 2009, Apple changed the MacBook back to plastic from aluminum. Along side, the RAM went from PC3-8500 DDR3 RAM to PC2-5300 DDR2 RAM. The maximum amount of RAM stayed the same at 4GB.

In the fall of 2009 Apple introduced a brand new MacBook using a plastic unibody enclosure. Along side this update, Apple reused the PC3-8500 DDR3 RAM. The maximum RAM has remained the same at 4GB.

MacBook

Intel Core Duo Processor



1.83/2.0 GHz Core Duo (13.3" LCD)
PC2-5300 DDR2 SODIMM
Max RAM 2 GB


Intel Core 2 Duo Processor

1.83/2.0 GHz Core 2 Duo (Late 2006)
PC2-5300 DDR2 SODIMM
Max RAM 3 GB

2.0/2.16 GHz Core 2 Duo (Mid 2007)
PC2-5300 DDR2 SODIMM
Max RAM 3 GB

2.0/2.2 GHz Core 2 Duo (Late 2007)
PC2-5300 DDR2 SODIMM
Max RAM 4 GB

2.1/2.4 GHz Core 2 Duo (Spring 2008)
PC2-5300 DDR2 SODIMM
Max RAM 4 GB



Aluminum Unibody Enclosure



2.0/2.4 GHz Core 2 Duo (Fall 2008)
PC3-8500 DDR3 SODIMM
Max RAM 4GB

Plastic Enclosure



2.0 GHz Core 2 Duo (Early 2009)
PC2-5300 DDR2 SODIMM
Max RAM 4GB

Plastic Unibody Enclosure



2.0/2.4 GHz Core 2 Duo (Fall 2009)
PC3-8500 DDR3 SODIMM
Max RAM 4GB