Will pc100 ram and pc133 ram work together? Or, will they interchange on the motherboard? My thunderboard motherboard bit the dust. It has 448m of pc100 ram in it. I am now using a dell, about 3 years old, that has 384m of pc 133 ram on it. Just wondered if I can use them together or will they even fit. Not sure what the motherboard is in the dell but it has a Pentium 3 processor. It also has windows ME. I had XP on the other computer. Would like to put XP on this one but I understand that MS won't let me do that. They won't even answer me on that question.