c:\test>each-keys-b -M1=keys -M2=pairs -N=8e6
hash built, starting timer
Took 899.040000 and 343.402MB extra memory for 8000000 using keys/pairs method

c:\test>each-keys-b -M1=each -M2=pairs -N=8e6
hash built, starting timer
Took 11.112000 and 0.023MB extra memory for 8000000 using each/pairs method