i just opened my pc but i could not see any nummer 400/533/600 on the label, but i saw in the mohterboard book there is somting with DDR (533 MHz) qualifirf vendors list with ram size,model,side ectmm but have no ide what is it... but i see in the book there is a nummer for a my kingston ram (KVR533D2N4/512 i also see that nummer on my 2x 512 MB ram block..