8GB KIT 2x 4GB Gateway DX DX4860-UB20P DX4860-UB21P DX4860-UR20P DX4860-UR21P DX4860-US20P DX4320-09 DX4840 DX4850 Series DX4850-27e DX4850-27EU DX4850-45 DIMM DDR3 NONECC PC3-10600 1333MHz RAM Memory 8GB KIT (2 x 4GB) DIMM DDR3 NON-ECC PC3-10600 1333MHz RAM Memory Genuine A-Tech Memory Lifetime Warranty Toll Free Technical Support 1-866-557-4527 Designed For Gateway DX Series. (See Compatibility List Below)