Please Read!!

The total capacity of these two modules together is 1 GB. You will receive 1 GB in total of DDR1 SDRAM. In (2 x 512 mb) modules

Kingston should have clarified this better as the part number, "KVR400X64C3AK2/1G" gives the impression that the module is 1 GB. It is not. It says underneath that,  "Kit of 2", which means you need both modules of the kit. When I bought this I thought I was getting two gigabytes because of the part number.

Again it's: 1GB total ( 2 modules x 512MB KIT)