Comparison of the speed of the hosting file subsystem and my hard drive. Why?

Question

Network administration

There is hosting from DigitalOcean.com that uses an SSD.
There is hosting from Flops.ru, where SSD is also used.
And there is my WD 1TB hard drive of the green series.
I launched a recording test on all 3 sites with the command:

sync; dd if=/dev/zero of=tempfile bs=1M count=1024; sync

Here is the output from
DigitalOcean:

1073741824 bytes (1.1 GB) copied, 20.908 s, 51.4 MB/s

Flops.ru:

1073741824 bytes (1.1 GB) copied, 50.0924 s, 21.4 MB/s

My hard drive:

copied 1073741824 bytes (1.1 GB), 5.41137 s, 198 MB/s

I ran a reading test with the command:

dd if=tempfile of=/dev/null bs=1M count=1024

Here is the output from
DigitalOcean:

1073741824 bytes (1.1 GB) copied, 3.04774 s, 352 MB/s

Flops.ru:

1073741824 bytes (1.1 GB) copied, 26.7436 s, 40.1 MB/s

My hard drive:

copied 1073741824 bytes (1.1 GB), 0.263673 s, 4.1 GB/s

I understand that hosting servers have more than one of my VPS, but still it seems to me that the speeds are very low and RAID on SSD, as the advertisement says, is not there.
Am I right?
PS For comparison, there is hosting from fastVPS.ru, the situation is as follows:
entry:

copied 1073741824 bytes (1.1 GB), 1.43735 s, 747 MB/s

reading:

copied 1073741824 bytes (1.1 GB), 0.239668 s, 4.5 GB/s