4GB PC2-6400 DDR2-800 240-pin 2Rx8 non-ECC unbuffered DIMM (p/n CJH) by Gigaram 4GB 240p PC2-6400 non-ECC non-Registered CL5 16c 256x8 DDR2-800 DIMM 100% Guaranteed Compatibility, please consult your motherboard manual to confirm compatibility.