{cp [n][y][n][y] is correct. Try four gigs first at stock settings (set RAM to 2.2v as required) and you won't need to up the NB voltage. Later, once you've verified dual channel mode is working via Everest, you can try 8. Unfortunately I don't know what settings you'll need to get it to work. It might work perfectly w/o adjusting voltages, or as Loonym suggested, you may need to reduce timings in addition to bumping up the NB. For starters though, lets just verify that dual channel mode is working with the 2 DIMMs.