Crucial 1GB kit (512MBx2) DDR2-667MHz (PC2-5300) CL5 Non-ECC 240-pin UDIMM Desktop Memory  - CT2KIT6464AA667 / CT2CP6464AA667 1GB Kit (2 x 512MB) DDR2 PC2-5300 1GB Kit (2 x 512MB) DDR2 PC2-5300