I believe the problem may be the motherboard's bios. It does not fully support the dual core processor even though the manufacturers claiming they are, Like shutlle sn25p, MSI, DFI. The return (rma) rate on DFI motherboard, that are running dual core, are 50%.
I think ECS is having a similar problem. Don't try to do too much. Or you motherboard and processor are going to fry.
You may have to wait for a bio update
On other hand, problem could be your memory's latency setting. Try a different stting.