Question Why is real-life file transfer much slower than what CrystalDiskMark shows during benchmarking my external NVMe SSD drive?

[neo4evr]

Hi,

I recently purchased the Asus ROG Strix Arion external SSD enclosure.

I had a Samsung 970 Evo Plus SSD. I installed the SSD in the Asus ROG external SSD casing.

On CrystalDiskMark, the write speed and read speed shows around 1000 Mbps.

However, during actual file transfer from my PC to that SSD, the write speeds stay somewhere around 700Mbps, which is 300Mbps less than what is shown in CrystalDiskMark.

I wish to know that is this normal thing to happen?

Why is the real-life file transfer so much slower than the benchmark score in CrystalDiskMark?

 

[PassMark]

Lots of reasons.
The max CrystalDiskMark score doesn't reflect real life very well.

• File transfer need to both read and write at the same time. Benchmarks don't, they either read OR write generally.
• File transfers need to update the master file table a lot (MFT is a separate hidden file on your hard drive that is the index for all the other files). Benchmarks don't need to do this very often.
• Benchmarks tend to use very large block sizes and large files. So if you are transferring small files, there is a lot more overhead. Difference can be enormous with USB latencies.
• Many SSD either overheat or run out of cache in a long copy operation. Benchmarks don't tend to run that long.