i get a max Rockstable of 530_ 570 on my connect 3d x800pro
vivo@XT..but i must say my GPU at default cannot match over 485Mhz...Ram was fine with 570Mhz ...
So i decided to make a Vcore Mode up to 1,5V..pretty fine now with 530Mhz for 2 Month..Temps fine..such an "healthy" lower VCoreMod isn'ta big risk ro Problem for the Lifttime or something else....with good cooling..
I suggest you too to use the Connect3d XT500_500 Bios, cause it gaves you the best OC of all avaible x800 Bios...
the best way to test satbility is the MotherNature Tets 3Dmarks03 (dont know 05 vers )...over hours (2-5) ,so you can test GPU ...for Mem take the Ragtrol Test! Gives you earliest Artifcts of all.