even if its only 5% margin, they build brand name, and that customer might buy other HP products, and also, the can pre-install select software as well as links and brower and have an effect on market. There is an advantage to having a big customer base. Also since they have a brand name, it helps it to sell other products such as servers and/other software solutions they may provide in the future. Also, there is extended warrenty they sell. So even if the PC is low margin, it leds to other sales. ANd since they are big they are able to borrow money if needed for other ventures, and they can buy in volume/parts for huge discounts. A lot of resouces are at their command. THe volume discounts and manufactor agreements may hrelp their other products suck as servers. So one effects another.