I have 1 GB of PC 3200 DDR ram(dual channel) and i have 1 GB of PC2700 DDR ram(dual channel). Obviously one set is faster than the other, and therefor I do not want my computers motherboard using the slower RAM, so i guess i shouldent put it in??. Basically, what i am asking is does the motherboard fill up the faster ram before it moves on to the slower ram? or does it fill up all 4 sticks randomly, because if so i do not want the slower ram in there because it would slow down my computer.