The big, and really only difference which is a major one is full support for FSB speeds of 133 and higher. The Pro2a (which uses KT133) even though the specs say it can go that high can't. All the KT133 chipset motherboards have this problem. You'll be lucky if you can get up 115 FSB on them. The KT133A chipset which is utilized by the Turbo has full support for 133 FSB and higher.