Why is my SSD write speed instead of 500 mb/s is 1-8 mb/s?

Question

linux

The performance of the SSD is 55,000 operations per second in blocks of 4 kb (in the worst situation, random reading, this is without fstreams and defragments). It's 224 mb/s. Serial 550 Mb/s.
In fact, I tested the performance with my program, it shows 1.2 mb / s -2.2 mb / s, while on a disk in RAM, it gives out 300 mb / s. In addition, this also confirms copying files to the SSD.

Answer 1

Because the maximum is indicated in ideal conditions.
That is, the disk is, in principle, capable of showing 55,000 IOPS when reading 4kb blocks.
It is possible - but only under certain conditions, not always.
A lot also depends on the FS, how exactly the FS works with the disk.
In general , all NAND SSDs show good IOPS only in large queue mode . No queue - there are gigantic delays and they ruin everything. (compared to hdd delays are scanty, but gigantic for such speeds)
If you need really large IOPS, look towards 3dXpoint memory from Intel and microns.

Answer 2

What will return

dd if=/dev/zero of=%раздел со смонтиролванным ssd%/tempfile bs=1M count=1024

?

Answer 3

Do you understand that the speed of file operations on a ram disk is tens of gigabytes per second?
And you have 300 megabytes. It's about the measuring device.