I have more than 20 SSDs from Crucial, Samsung, and other companies.
Let’s take the example of my Samsung 970 Plus 2TB which I use with a 10 Gbps USB C enclosure. On the product page it says that the SSD has a write speed of up to 3,300 MB/s.
When transferring RAW photos from my camera to this SSD, it sits between 500-1000 MB/s, which is expected via a 10 Gbps enclosure. However, after a short while, the write speed slows down to 30-50 MB/s, which is even worse than that of a mechanical hard drive!
On my Crucial x4 4TB (via a 10 Gbps USB C cable), the behavior was even worse. I was transferring copying some files internally from one folder to another. It started out at ~200 MB/s, but then slowed down to 45 MB/s after just two minutes of copying files.
I have experienced this behavior across most of my SSDs. Why does the write speed on my SSDs slow down so significantly after writing to them for a few minutes? How do I avoid this? It’s frustrating since I bought all these SSDs to be able to transfer data to them much faster than I would with a mechanical drive.
I did some of my own research and got some possible explanations, but none of them seem plausible:
- Thermal throttling: I’ve felt these drives and they barely get hot at all during the data transfer. The 970 Plus is in a metal enclosure, connected via a thermal pad. Also, I wouldn’t expect it to throttle after such a short amount of time if it’s being written to at 25% of its rated write speed.
- Write amplification: From my understanding, this shouldn’t be an issue since this happens even with a newly formatted SSD.
