System worked fine when I had my Athlon 2000 and 3 sticks of 512mb Crucial PC 2100 ram. I upgraded to an athlon 2600 (333mhz FSB) and 3 sticks of 512mb PC2700 crucial. When all 3 sticks are installed windows XP pro will give BSOD with some memory errors. When any 2 of the 3 are installed I have no problems. Also when all 3 are installed but the memory is under clocked to 266 there is no problem. any ideas?