There's a good combo using the 163x27 which I was running at first. It was about 4.41 or so with 1960Mhz 3920 Uncore which is very decent i was running it on 1.39 vQPi so you can try that if you like. You may also need to raise PLL to >1.8. You see for daily use Intel max QPIv is 1.4 so you may need to lower the uncore below 2xDRAM to stay under 1.4. Up to you really