[root@zjx86r01n01 tmp]# time dd if=/dev/zero of=/tmp/testfile.dat bs=8k count=1024
1024+0 records in
1024+0 records out
8388608 bytes (8.4 MB) copied, 0.0415268 s, 202 MB/s
real 0m0.079s
user 0m0.000s
sys 0m0.019s
[root@zjx86r01n01 tmp]# time dd if=/tmp/testfile.dat of=/dev/null bs=8k
1024+0 records in
1024+0 records out
8388608 bytes (8.4 MB) copied, 0.00453069 s, 1.9 GB/s
real 0m0.008s
user 0m0.002s
sys 0m0.004s
[root@zjx86r01n01 tmp]#