-[dps@neve]-[~]--
> sync;time bash -c "(dd if=/dev/zero of=outputfile1 bs=8k count=1000000; sync)"
1000000+0 records in
1000000+0 records out
8192000000 bytes (8.2 GB) copied, 114.3 s, 71.7 MB/s

real    2m38.449s
user    0m0.097s
sys     0m12.537s

--[dps@neve]-[~]--
> sync;time bash -c "(dd if=/dev/zero of=outputfile2 bs=8k count=500000; sync)"
500000+0 records in
500000+0 records out
4096000000 bytes (4.1 GB) copied, 31.8734 s, 129 MB/s

real    1m17.829s
user    0m0.093s
sys     0m5.860s

--[dps@neve]-[~]--
> sync; time bash -c "(dd if=/dev/zero of=outputfile3 bs=8k count=131072;sync)"
131072+0 records in
131072+0 records out
1073741824 bytes (1.1 GB) copied, 1.09095 s, 984 MB/s

real    0m26.068s
user    0m0.003s
sys     0m1.317s
--[dps@neve]-[~]--
>