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
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