What is your block size parameter? $ dd bs=100000 if=aaa of=bbb Block size makes a big difference to performance. Cheers -- Rick On August 28, 2022 10:55:44 p.m. EDT, James <bjlockie [ at ] lockie [ dot ] ca> wrote: >I had an HP EX900 - 250GB nvme that I upgraded to a Samsung SSD 980 - 500GB. >I figured the new one would be twice as fast but I don't notice a difference. >The m.2 slot is PCI 3x4. >Is the dd read of 200 MB/s the same scale as the the Timing buffered disk reads of ~2000 MB/sec? >It looks the new one is 10x faster but it wasn't noticeable like I expected. > >$ sudo dd status=progress if=/dev/nvme0n1 of=/media/lubuntu/hdd-storage/storage/backups/HPEX900nvme0n1.iso >249912431104 bytes (250 GB, 233 GiB) copied, 1251 s, 200 MB/s >488397168+0 records in >488397168+0 records out >250059350016 bytes (250 GB, 233 GiB) copied, 1252.98 s, 200 MB/s > > >This is my new Samsung SSD 980: > >$ sudo hdparm -tT /dev/nvme0n1 > >/dev/nvme0n1: > Timing cached reads: 23550 MB in 2.00 seconds = 11797.37 MB/sec > Timing buffered disk reads: 6110 MB in 3.00 seconds = 2036.20 MB/sec > > >$ sudo hdparm -tT /dev/nvme0n1 > >/dev/nvme0n1: > Timing cached reads: 20628 MB in 2.00 seconds = 10332.71 MB/sec > Timing buffered disk reads: 6212 MB in 3.00 seconds = 2069.96 MB/sec > > >$ sudo hdparm -tT /dev/nvme0n1 > >/dev/nvme0n1: > Timing cached reads: 22978 MB in 2.00 seconds = 11510.18 MB/sec > Timing buffered disk reads: 6008 MB in 3.00 seconds = 2002.28 MB/sec > > >To unsubscribe send a blank message to linux+unsubscribe [ at ] linux-ottawa [ dot ] org >To get help send a blank message to linux+help [ at ] linux-ottawa [ dot ] org >To visit the archives: https://lists.linux-ottawa.org > -- Sorry for being brief. Alternate email is rickleir at yahoo dot com