The 6 cores have half the write bandwidth, but thinking on this further (after this evenings testing), your read and copy might be low due to memory interleaving size. I get similar results at 2KB, try changing it to 512. Just following up on this, I tested dual rank sticks vs single rank sticks with identical settings (same profile). Bandwidth is roughly within margin of error, but the latency is significantly down. So I guess that answers that one. Click to view full size!