An efficiency enchantment only applies to blocks that the tool is appropriate for. For example: mining a wooden blok with an efficiency IV pickaxe is as fast as mining it with your hand.
MC-4645
The speed increase of efficiency ONLY applies to blocks that the tool is appropriate for.
Resolved
Works As Intended
0
Ruben
(Unassigned)
Unconfirmed
Snapshot 12w50b
Retrieved
Well that sucks...