FWIW, I see the opposite behavior when $key = 'lazy'; (I.E. when $key matches often): 
      Rate    lb    nl   sol
lb  10.3/s    --  -91%  -91%
nl   109/s  965%    --   -9%
sol  120/s 1066%    9%    --

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In reply to Re^2: Inexplicably slow regex by duckyd
in thread Inexplicably slow regex by Anonymous Monk

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