Why does the speed of copying from a local disk to a local one jump so much?

Question

Solid State Drives

Hello.
I copied a number of files (about a hundred, 300-500 mb in size) from one local disk to another (both on the same SSD). The speed was extremely disappointing, the first seconds it was around two hundred megabytes, but then it dropped and began to fluctuate between 80 and 2-3 mb. On average 20-30. This prompted me to check the disk with Victoria. The Good status certainly pleases, but a lone red dot in the health column in the raw read error rate line nullifies the joy. Tell me, how much the picture and in particular this item should disappoint and what should be done?
Thank you.

Answer 1

Because the drive is budget.
https://www.overclockers.ua/storage/kingston-ssdno...

In real scenarios of copying a large amount of information, the controller does not have time to cope with an intensive load, which leads to a short-term sag in the write speed up to 3–5 MB / s.

Answer 2

Why does the speed of copying from a local disk to a local one jump so much?

Because you are copying to the same disk you are reading from.

the first seconds was around two hundred megabytes,

Of course, the cache in RAM is what the system needs for this.

but then it fell and began to fluctuate between 80 and 2-3 mb.

This indicates that the budget disk is packed to capacity, or TRIM does not work.
Take a normal disk capable of holding the load, or don't fill it to capacity, leave a decent amount of margin for the unused part of the disk.

but a lone red dot in the health column in the raw read error rate line nullifies the joy

Why? Don't like the red color?

Answer 3

logical partitions within the same physical disk (especially ssd) very rarely make sense. this way you simply load the controller and disk in situations where you can get by with just editing file descriptors.
and yes, your ssd is not able to keep high speeds for a long time, alas.