C:\test>p1
print mem;;
9,356 K

$#keys = 10e6; $#values = 10e6; $keys[ $_ ] = "$_", $values[ $_ ] = $_ for 0 .. 10e6;;
print mem;;
2,000,088 K

@hash{ @keys } = @values;;
print mem;;
4,394,716 K

print size( \%hash );;
783106748