sub x{}; 
cmpthese -1,{ 
    a=>q[ x( 1..1e6 ) ], 
    b=>q[x( [1..1e6] ) ] 
};;
    Rate    b    a
b 10.5/s   -- -56%
a 23.8/s 126%   --

@a = 1 .. 1e6;;
cmpthese -1,{ 
    a=>q[ x( @a ) ], 
    b=>q[x( \@a ) ] 
};;
       Rate         a         b
a    24.1/s        --     -100%
b 2903218/s 12025922%        --