Lets go ahead and list the reasons Froome climbed almost as fast as Armstrong on AX3:
Earlier in the race
Wind conditions
Temperature conditions
Superior training techniques
Lighter bikes
Warm downs
Cadence
Pedaling efficiency
Ritchie Porte pushing him in training
He's from Kenya
Now, all of those who think that was normal can just lurk. No need to write anything as I did the work for you. You're welcome.
Earlier in the race
Wind conditions
Temperature conditions
Superior training techniques
Lighter bikes
Warm downs
Cadence
Pedaling efficiency
Ritchie Porte pushing him in training
He's from Kenya
Now, all of those who think that was normal can just lurk. No need to write anything as I did the work for you. You're welcome.