the agp bottleneck is a hoax. ignore the marketers. you got a card going a million miles an hour, there is no cop wth a radar gun and spike strips at the end of the agp slot...it is going to keep on going...
which gets me to my only problems ever...
memory speed of card way mismatched to the system. I stopped upgrading my ht 3.4 prescott at the ati 3650, 400mhz ddr2 ram...and that is another hoax..they added channels to ram like hyper threading. the 400mhz is actually something else on a prescott than it is for a 533bus on same chipset. (I lived it first hand)
I say no to the 1333mhz ddr3, but its up to you..you have an intel 3.4 on via..and a tiny board, you like the risks of crazy fun.
go for it...