text: which is better pc2100 or pc2700? i actually know which is better but because i have been out of it for a while. i have a 256 pc2700 and a 512 pc2100 no i do know it will make the pc operate at 2100 speed , but is it really that noticable. how much speed am i losing? depends. pc2700 is better because it is faster memory than pc2100. but, remember, if you have a pc/laptop that accepts pc2100, then you can put a pc2700 memory in it but it will not make your laptop faster. it works only because all memory modules are backward compatible and work with old slots but will not be able to take advantage of the speed capabilities of the newer memory modules.