I have been using the MacBook for sometime now..and am no newbie to mac os x. and I have even consulted so many engineers and they have been unable to come up with a satisfactory answer. unfortunately, there is no genius bar over here. so.. how come I have 1GB of RAM in my computer but can use only half of it. In the activity monitor, about 250MB goes in the red or the wired region and the inactive or the blue region never goes below 250MB. at at time, even under the heaviest use the active or the yellow region is never above 500. also, under the sstem profiler, both the DIMMs are OK. so..can someone please explain why this is so..or is it a problem with my MacBook? p.s : I have typed using my iPhone so please excuse any grammatical or other errors!