binstub vs bundle exec

gistfile1.txt

require 'benchmark/ips'

Benchmark.ips do |x|
  x.config(time: 60, warmup: 5)
  x.config(stats: :bootstrap, confidence: 95)
  x.report('binstub') { `bin/rspec -v`}
  x.report('bundle exec') {`bundle exec rspec -v `}
  x.report('direct') {`rspec -v `}
end

gistfile2.txt

Warming up --------------------------------------
             binstub     1.000  i/100ms
         bundle exec     1.000  i/100ms
              direct     1.000  i/100ms
Calculating -------------------------------------
      1.608  (± 1.1%) i/s -     97.000  in  60.534547s
      1.477  (± 0.6%) i/s -     89.000  in  60.315969s
      2.828  (± 0.8%) i/s -    170.000  in  60.313360s
                   with 95.0% confidence