ATi Crossfire X Logo amp; Performance Scaling

CJ showed us how the ATi Crossfire X logo looks like and boards will use thislogo if they are certified for multi-GPU (Tripod or Quad). AMD revealed theperformance scaling for Crossfire X as below :

1 GPU = 1 x performance
2 GPU = 1.8x performance
3 GPU = 2.6x performance
4 GPU = 3.(?)x performance