I came to post the same thing, and got similar results: Accumulate took 0.00195327 seconds ToString() took 0.00283577 seconds. Join

I came to post the same thing, and got similar results: Accumulate took 0.00195327 seconds ToString() took 0.00283577 seconds. Join took 0.00462704 seconds. stringstream took 0.00084927 seconds. The relative speed improvement was -71.1482%