yeah seems odd if it worked before, just a thought, i've got crucial ballistix ram and had all sorts of problems with them a while ago when i first got them, I believe it turned out that increasing the FSB on my mobo caused an automatic increase in vdimm (im on an older asus board), and my ram was getting to much juice, forget what my vdimm is now but you could try setting vdimm lower, start below 2V and see what happens.