The cause of your excessive completion times is undoubtedly caused by virtual-memory thrashing,
More utter bollocks!
Unless the OP is running his program on a 10 year old machine, then 1/2GB of ram:
@a = ('x'x70)x2e6;;
@b = @a;;
print total_size( \@a ) + total_size( \@b );;
Is very unlikely to be the cause of his problem.
His problem is entirely down to the use of a crazy algorithm inside the module he chose to use.
Once more you are sending OPs down blind alleys with your home-spun 'wisdoms".
With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.