Why is the SSD on my MBP so slow?

[Faize]

This shouldn't take "about 5 seconds" (which turned out to be closer to 30), it should happen faster than I can blink.

For reference, this is a 1 TB SSD on a 2023 M2 Pro MBP. Even a bargain basement QLC SATA SSD is faster than this.

 

[Honza1]

Run Disk Utilities First aid on it to check for any issues. When my SSD eventually failed, first obvious issues was it was much slower than expected. Good luck.

 

[chown33]

How full is the SSD?

Are only the reads slow, only the writes, or are they both slow?
A disk benchmarking app would show both numbers.
Otherwise there are Terminal cmds that can produce the numbers.

 

[bradbomb]

Also, what is the source of the copy? Is this a copy to and from different folders on the same SSD or is it on a different drive?

 

[Honza1]

Also, what is the source of the copy? Is this a copy to and from different folders on the same SSD or is it on a different drive?

Good point about the source, that could have major influence.
But if the copy would be from the same drive (just different folder), APFS Apple uses today will not copy anything, just make link to the same data and speed will be very high and independent of file size. APFS simply records that the same data are used in different file second time and is done.

 

[Nermal]

How many files are being copied? Typically a bunch of tiny files take a lot longer to copy than a few big ones.