I used to run half a dozen AL-8's in my old test-suite and they are brilliant motherboards, but that Northbridge runs REALLY warm, even with the fan running. By all means try it though - set the NB temperature alarm to shut down quite low and give it a shot. It's not a very big heatsink - you might be better to replace it with a Noctua or Thermalright HR-05 type if you want to run passive.