詳細如link: http://www.brighthub.com/computing/hardware/articles/48391.aspx
裏面說著… Triple-Channel DD3 and Dual-Channel Memory The original Core i7 products, and their associated X58 chipset, main use of triple-channel DDR3 memory. This meant that it was best to purchase RAM sticks in multiples of three. This is a turn off to many users because it makes RAM less flexible and requires more spending upfront. Gamers may enjoy spending the money to see the i7 really perform.
Core i5, however, uses traditional dual-channel memory. This should make RAM less expensive for most users. Some new Core i7s will also support dual-channel memory instead of triple-channel. The performance difference should be insignificant for most users.