Windows file copy slow

[NunoLava1998]

CrystalDiskMark shows speeds of 1500MB/s sequential read 650MB/s sequential write for my NVMe with 4KQ1T1 speeds being around 120~130MB/s (which is my drive's advertised specifications); however when I do a file copy in Windows (using robocopy, File Explorer, doesn't matter) it always tanks down to anywhere between 100kb/s and 1mb/s. How can I fix this? My drive is a Optane 800P 58GB. How much the drive is filled doesn't matter at all

 

edit: mods please move this to troubleshooting im sutpid

[NunoLava1998]

Doesn't seem to be an issue with the drive at all as this also happened with my older SATA SSD (Patriot Burst 240GB)

[Mira Yurizaki]

How many files are you transferring?

[NunoLava1998]

1 minute ago, Mira Yurizaki said:

How many files are you transferring?

Doesn't matter it seems. I did a quick test with robocopy with 32MiB of files each 4096 bytes (8192 files) and it still did that; moving program folders (which are quite similar) does the same.

[Mira Yurizaki]

Just now, NunoLava1998 said:

Doesn't matter it seems. I did a quick test with robocopy with 32MiB of files each 4096 bytes (8192 files) and it still did that; moving program folders (which are quite similar) does the same.

Well, higher file count results in file system processing overhead tanking the transfer rate. Benchmarks doing 4K testing doesn't reflect this since it's accessing the same file.

 

What happens if transfer a single file of relatively large size (say 1 GiB)?

[NunoLava1998]

10 minutes ago, Mira Yurizaki said:

Well, higher file count results in file system processing overhead tanking the transfer rate. Benchmarks doing 4K testing doesn't reflect this since it's accessing the same file.

 

What happens if transfer a single file of relatively large size (say 1 GiB)?

Pretty instant; seems like it's only an issue with small files. I bought the drive for the 4K performance though and most of the files i copy/move are small so..

[Mira Yurizaki]

1 minute ago, NunoLava1998 said:

Pretty instant; seems like it's only an issue with small files. I bought the drive for the 4K performance though and most of the files i copy/move are small so..

But again, 4K benchmark tests do not account for file system processing overhead. You can tell robocopy to use more threads to speed up the process: https://pureinfotech.com/robocopy-multithreaded-file-copy-windows-10/

[NunoLava1998]

Just now, Mira Yurizaki said:

But again, 4K benchmark tests do not account for file system processing overhead. You can tell robocopy to use more threads to speed up the process: https://pureinfotech.com/robocopy-multithreaded-file-copy-windows-10/

Thing is; CrystalDiskMark uses only 1 thread and still gets that 130mb/s speed. Plus measuring it remotely (i'm benchmarking it as a boot drive) gives even higher speeds

[Mira Yurizaki]

4 minutes ago, NunoLava1998 said:

Thing is; CrystalDiskMark uses only 1 thread and still gets that 130mb/s speed. Plus measuring it remotely (i'm benchmarking it as a boot drive) gives even higher speeds

However it's accessing the same file (so the SSD knows exactly where to look) and it's not touching the file system after the test file was created. Copying files around touches the file system for every file copied.

[NunoLava1998]

2 minutes ago, Mira Yurizaki said:

However it's accessing the same file (so the SSD knows exactly where to look) and it's not touching the file system after the test file was created. Copying files around touches the file system for every file copied.

Thing is, i'm pretty sure this also happened with my earlier SSD at the exact same speeds when copying

[Mira Yurizaki]

1 minute ago, NunoLava1998 said:

Thing is, i'm pretty sure this also happened with my earlier SSD at the exact same speeds when copying

What was your last SSD?

[NunoLava1998]

Just now, Mira Yurizaki said:

What was your last SSD?

Patriot Burst 240GB. SATA SSD with DRAM cache that has about the same speeds as a BX500~MX500