*** This is Dual Rank Memory **** VERY IMPORTANT NOTE: Please check your model server on the manufacturers website that it will accept the quantity of memory you desire to install. Some servers will only accept 8 ranks total. Therefore, if you purchase Dual Rank that counts as 2 ranks and will only allow you to install 4 sticks total in your server for 8GB total. Therefore, we highly recommend contacting the manufacturer before your purchase if you intend to install more than 8GB. We are finding that the Single Rank 2GB memory is more expensive and also difficult to source. Therefore, we only stock the Dual Rank 2GB sticks. If you have any questions about whether your computer can accept Dual Rank, please contact the manufacturer. ************* If you buy the Dual Rank, please update your Server/Workstation BIOS to the latest version from the manufacturers website. Make sure to read their cautions before updating. *************** Many servers that the manufacturer says can only accept 12GB can be easily pushed to the 16GB undocumented maximum of 16GB (4x4GB) with the latest BIOS update from the manufacturer! SEARCH OUR EBAY STORE FOR YOUR MODEL SERVER FOR THE 4GB MODULE LISTINGS ****** Highly Recommended and proven with a money back guarantee: We also stock 4GB sticks for your server/workstation that accepts PC2-3200 ECC REG. They need to be installed in pairs. Single Rank: We have in stock regularly for the 1GB PC2-3200 (DDR2) ECC REG Dual Rank: We have in stock regularly for the 2GB PC2-3200 (DDR2) ECC REG Additional Details ------------------------------ Package quantity: 1