(Added this in Edit later: I hadn't realized that you were doubling up with two similar message threads in the same forum, or I would have referred you from here back to the older thread.)
Although I am not familiar with any KT-333 motherboards, I do have several NF2's, and a couple of KT-266 - based MB's. Unless you replace the cpu, you probably are only gaining the onboard Sound Storm (on the Asus), if you can use it. Also, there have been two somewhat similar Abit NF2 motherboards. The "S2" and its twin, the "S2G" are both pure crap. Not worth $25, let alone $65!
The NF2 chipset motherboards are more popular in places such as Anand Tech's forums because they are easier to tweak. The AGP and PCI slots aren't affected by changing the FSB for the memory and cpu, for example. Via didn't have that locked AGP feature for the motherboards they made for Socket A.
MSI's Via motherboards are popular with white box system builders because they are less costly, but they aren't necessarily cheaply made. You "might" get some improvement from a faster cpu in the same motherboard, but that would be a more expensive option. If you want to see some seriously improved speed for gaming purposes, add $75 or so and look at this ad from Newegg:
http://www.newegg.com/Product/Product.asp?Item=N82E16814130220
That's a one day sale, 6600GT for $155.
:thumbsup: