A-TECH 8GB KIT (4 x 2GB) For Dell Optiplex 740 745 745c 755 DT/MT / SFF 755. DIMM DDR2 NON-ECC PC2-5300 667MHz RAM Memory. Genuine Brand. 8GB KIT (4 x 2GB) DIMM DDR2 NON-ECC PC2-5300 667MHz RAM Memory Genuine A-Tech Memory Lifetime Warranty Toll Free Technical Support 1-866-557-4527 Designed For Dell Optiplex. (See Compatibility List Below)