Kingston 2GB (2 x 1GB )
Part Number: KVR667D2N5/1G
Specs: DDR2, 667MHz, PC2-5300, Non-ECC, CL5, 1.8V, Unbuffered, DIMM
hynix 2GB (2 x 1GB )
Part Number: HYMP512U64BP8-Y5 / PC2-5300U-555-12
Specs: DDR2, 667MHz, PC2-5300, Non-ECC, CL5, 1.8V, Unbuffered, DIMM
Total 4 x 1 Gigabyte DIMM
$20 each module OR $70 for all 4 modules