I just ordered a slot a 800 thunderbird for my Ka7, i will get it on tuesday. I have heard that most people who have attempted on a kx133 chipset have had success @ 800 and below, i even found this webpage on the abit site stating that the most success ahs been found on a tbird 800.
so here's hoping(fingers crossed). Also, the irongate(amd 750) chipset officially supports the tbird