Well they are what they say "slimcases". Many systems sold today fall into many different categories. FullTower ATX, Mid-Tower ATX, Micro-Tower, Slim Tower, Mini-ITX. This is due to the different sizes of mainboards being produced. Full ATX (13.25"x12.00") to Mini-ITX (6.69"x6.69"). With Slim Towers you reduce the height and width of the case for added space on a desk. Add a LCD screen and you save quite abit of space. The draw back to a case like this is the amount of options you have to work with when adding components. You will commonly find a case and board like this supporting: 1 Floppy Drive, 1 Optical Drive, 1 Hard Disk, 2+ Dimms for memory, Multiple array of Processors, Smaller power supplies 200watts, and a series of onboard components [Video, Lan, Audio, Networking etc]. Because of all the onboard components you save quite a bit of money overall. Recently I built a system using: Aopen H340D slimcase, Asus A7N266-VM mainboard, Kingston DDR 266, Aopen CRW5232, AMD XP2000+, WD80GB, KB/M, 17" Viewsonic Monitor = Approx. $560