There is a difference in bandwidth capacities, and I'm sure you already figured that each generation thus far is double the previos generations, If you read on in that article at tommies hardware's, you notice that "current" applications and even hardware don't yet make use of the added fill rate capabilities of 8x and in many cases 4x agp. But if you're building a machine from scratch and don't intend on upgrading your mobo within the next 2 years, I'd say go for it, they have better memory controllers and are generally faster mobo's anyway, plus if you purchase any software that will benefit from agp 8x (like DOOM III) you'll be glad you went ahead with the purchase. just my 2 centavos (spanish for pennys).