I bought this product for my old Dell Dimension XPS-T450 to extend its usefulness. As I was unaware of that the maximum RAM for each slot was 256MB, the computer read as 256MB instead of 512MB. With the seller's outstanding assistance I successfully installed two replaced 256MB memories to get total 512MB, the system is now working fine and steadily. It is worth spending $28 to keep the old computer working as an experimental machine.