Im guessing you are speaking of ITX based computers,well they don't have as good of cooling solution, so they normally use a cooler electionics setup,aka, slower setup, than that a same price mid tower based.
EDIT:If you are thinking of a netbook,(A micro laptop,about 10 inch screen),then its about the same story as above just the fact that they are even slower,as they have to run very cool and verrry efficient setups,such as an Intel atom cpu.
Personally if portability is a big issue then go right ahead and buy a netbook,but the sacrifices made to have a netbook,if you ask me,aren't worth it,they are so underpowered,that they need to run windows XP,they don't meet the Vista system requirements and are essentially locked into their current setup,It gets worse,the new windows 7 based netbooks will come with the worst version,starter basic,of which on you can't even change the background!
You can buy a full size,fully capable, vista notebook for $150 moreItx based PCnetbookGood priced full sized laptop.
Edited by sonicjet, 21 July 2009 - 07:36 PM.