I have just decided to upgrade my RAM from two sticks of 256MHz(512Mhz total) to 1.5GHz by adding a new 1GHz.I was careful to buy the same speed ie DDR-400MHz PC3200. When I fitted the new 1GHz module into the motherboard(ECS 648FX), the PC went ape. I took the 1GHz out and the system started normally again, after telling me that it had receovered from a serious error. I then took out the two 256GHz modules and left just the 1Ghz in there. This too worked OK. I then added one of the 256MHz and that was OK but when I added the second one, the PC rejected that again.However,I was quite keen to have all three installed. At present I have one 256MHz strip and one 1GHz strip fitted and that seems OK. Am I stuck with just these two or am I doing something in the wrong order?