Per the sibling comments, you just need to specify a sane block size. dd's default is really low and if you experiment a bit with 2M or around that you'll get n

Per the sibling comments, you just need to specify a sane block size. dd's default is really low and if you experiment a bit with 2M or around that you'll get near-theoretical throughput. NB: Remember the units! Without the units you specify it as bytes or something insanely small like that. I've made that mistake more than once!