First of all, the i7 packs a new architecture and comes in a new cpu socket, so u will have to buy a new mobo. Also i7 mobos only accept DDR3 memory. These components makes the entry-level i7 platform a lot more faster than any previous dual or quad core , even the $1000 extreme editions. Also, the i7 features 2 processing threads per core, so u will virtually have 8 cores (thats the way is shown to the OS). As someguy7 said, the i7 platform cost a lot more, but the performance is just amazing. If u have the bucks, definitely buy it.