----- READ -----

$ dd if=test.garbage bs=4096 | pv > /dev/null
40960000000 bytes (41 GB, 38 GiB) copied, 226.184 s, 181 MB/s

$ dd if=test.garbage bs=4096 | pv > /dev/null
40960000000 bytes (41 GB, 38 GiB) copied, 233.655 s, 175 MB/s

----- WRITE -----

$ dd if=/dev/zero bs=4096 count=10000000 | pv > test.garbage
40960000000 bytes (41 GB, 38 GiB) copied, 127.142 s, 322 MB/s

$ dd if=/dev/urandom bs=4096 count=10000000 | pv > test.garbage
40960000000 bytes (41 GB, 38 GiB) copied, 245.921 s, 167 MB/s

----- DEV -----

$ dd if=/dev/zero bs=4096 count=10000000 | pv > /dev/null
40960000000 bytes (41 GB, 38 GiB) copied, 14.8122 s, 2.8 GB/s

$ dd if=/dev/urandom bs=4096 count=10000000 | pv > /dev/null
40960000000 bytes (41 GB, 38 GiB) copied, 212.95 s, 192 MB/s