time -p dd if=/dev/sda5 of=/dev/null bs=1024k count=1024
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 25.2325 seconds, 42.6 MB/s
real 25.26
user 0.00
sys 1.82

This transferred 1 gigabyte of data in 42.g megabytes per second.