$ perl -MBenchmark -e'timethese(10000, { map => sub { @_ = map 1, 1..1000 }, x => sub { @_ = (1)x1000 }})'

Benchmark: timing 10000 iterations of map, x...
       map: 29 wallclock secs (27.09 usr +  0.24 sys = 27.33 CPU) @ 365.90/s (n=10000)
         x: 14 wallclock secs (13.36 usr +  0.09 sys = 13.45 CPU) @ 743.49/s (n=10000)

$ perl -MBenchmark -e'timethese(1000000, { map => sub { @_ = map 1, 1..5 }, x => sub { @_ = (1)x5 }})'

Benchmark: timing 1000000 iterations of map, x...
       map: 17 wallclock secs (15.55 usr +  0.15 sys = 15.70 CPU) @ 63694.27/s (n=1000000)
         x:  9 wallclock secs ( 8.44 usr +  0.11 sys =  8.55 CPU) @ 116959.06/s (n=1000000)