8GB KIT 4 x 2GB HP-Compaq Business Desktop Series dc7800 dx7400 DIMM DDR2 NON-ECC PC2-5300 667MHz RAM Memory Genuine A-Tech 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 HP-Compaq Business Desktop Series. (See Compatibility List Below)