gistfile1.txt

                   Run 1   Run 2   Run 3   Run 4   Run 5   Average
rake spec          119.10  99.09  101.29  100.89   97.69   103.61
rake parallel:spec  90.86  90.19   91.06   87.99   90.63    90.15

                                             Time savings   13.46
                                             Savings as % of orig = 12.99%


Source data:

[09:01-focus!][weplay(pspecsΔ)]$ echo 'rake spec' && time rake spec && echo 'rake parallel:spec[2]' && time rake parallel:spec[2]
rake spec
real    1m59.095s
user    1m18.679s
sys     0m7.996s

rake parallel:spec[2]
real    1m30.863s
user    1m27.607s
sys     0m10.645s

rake spec
real    1m39.085s
user    1m17.738s
sys     0m7.818s

rake parallel:spec[2]
real    1m30.191s
user    1m27.333s
sys     0m10.697s

rake spec
real    1m41.289s
user    1m17.964s
sys     0m7.874s

rake parallel:spec[2]
real    1m31.064s
user    1m27.845s
sys     0m10.623s

rake spec
real    1m40.885s
user    1m17.740s
sys     0m7.944s

rake parallel:spec[2]
real    1m27.991s
user    1m27.421s
sys     0m10.620s

rake spec
real    1m37.689s
user    1m17.556s
sys     0m7.849s

rake parallel:spec[2]
real    1m30.633s
user    1m27.279s
sys     0m10.735s