Using + to spread strings across multiple lines is slower than using \

string_timings.rb

def timer
  start_time = Time.now
  1_000_000.times do
    yield
  end
  Time.now - start_time
end

time_a = timer do 
  x = "this this this this this this this this this this this this this this this " +
      "that that that that that that that that that that that that that that that " +
      "this this this this this this this this this this this this this this this " +
      "that that that that that that that that that that that that that that that " +
      "this this this this this this this this this this this this this this this " +
      "that that that that that that that that that that that that that that that " +
      "this this this this this this this this this this this this this this this " +
      "that that that that that that that that that that that that that that that " +
      "this this this this this this this this this this this this this this this " +
      "that that that that that that that that that that that that that that that " +
      "this this this this this this this this this this this this this this this " +
      "that that that that that that that that that that that that that that that "
end

time_b = timer do 
  x = "this this this this this this this this this this this this this this this " \
      "that that that that that that that that that that that that that that that " \
      "this this this this this this this this this this this this this this this " \
      "that that that that that that that that that that that that that that that " \
      "this this this this this this this this this this this this this this this " \
      "that that that that that that that that that that that that that that that " \
      "this this this this this this this this this this this this this this this " \
      "that that that that that that that that that that that that that that that " \
      "this this this this this this this this this this this this this this this " \
      "that that that that that that that that that that that that that that that " \
      "this this this this this this this this this this this this this this this " \
      "that that that that that that that that that that that that that that that "
end

puts "With '+': #{time_a}"
puts "With '\\': #{time_b}"