Issues with NVMe to USB Adapters Causing Slow Transfer Speeds

Cards, Drive Accessories, Tools
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Hello

I recently bought an NVMe to USB adapter to use my spare NVMe SSD as an external drive. While it works; I’ve noticed that the transfer speeds are significantly lower than expected. The SSD is rated for high speeds; but I’m only getting a fraction of that when transferring large files. :innocent:

I’ve tested different USB ports, cables & even another NVMe drive, but the issue persists. I suspect it could be a limitation of the adapter itself, possibly related to the controller or power delivery. Has anyone else faced similar issues with NVMe to USB adapters? :thinking: Are there specific brands or chipsets known for better performance? :innocent: I checked Cards, Drive Accessories, Tools - The IT Pro StarTech.com CommunitySplunk course resources, and found it quite informative.

Would appreciate any recommendations for troubleshooting this / suggestions on reliable adapters that can deliver full NVMe speeds. :innocent: Also, if there are any driver or firmware updates that could improve performance, I’d love to know.

Thank you !! :slightly_smiling_face:

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Hi there @savaneb, thanks for the post.

I’ll try to cut tot eh chase here, but in most cases, USB speeds are going to be quite a lot slower than your average NVMe M.2 drive, so you will see reduced performance in most cases. This is because the NVMe protocol is just much faster in most cases.

On average, USB enclosures are in the 5 to 10 Gbps range, which to convert to MB/s as that’s how most NVMe drives list their speed, is about 625MB/s to 1,250MB/s. However, even low-end NVMe drives are going to average around the 1,000 MB/s mark, and most are in the 3,000+ range.

So, what you’re seeing is a mismatch of the speed of the USB NVMe adapter with the speed of your drive. With computers, whatever is the slowest speed governs the whole thing.

So, let’s say you got a nice fancy PCIe 5.0 NVMe drive that has a read and write speed of 12,000 MB/s, and a USB4 enclosure that can support 5,000 MB/s. If you connect that to a USB4 port, you’ll get, at most, 5,000 MB/s. However, if you connected it to a USB 2.0 port, you’d drop all the way down to 60MB/s as that’s the cap for USB 2.0.

In terms of adapters that can deliver full NVMe speeds? Basically none over USB. You can get some for Thunderbolt 3 that will make use of the proper protocols, but they only work for PCIe 3.0 x 2 and PCIe 3.0x4 drives for the most part at full speed. Thunderbolt 5 should work with PCIe 4.0 x 2 and PCIe 4.0 x 4, but I have yet to see a Thunderbolt 5 powered NVMe enclosure. Nothing exists for external PCIe 5.0 NVMe drives at full speed, those have to be internal.

If needed, I can further explain how to MB vs Mb, how to convert between, what things like PCIe 3.0 x 2 means and so on, but essentially you’re just running into a bottleneck because NVMe drives are so ridiculously fast compared to USB.

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Also, I forgot to ask, what’s the specific model of USB to NVMe you have from us, the specific NVMe M.2 you have in it, and the make and mode of computer you’re connecting it to? With that, I can use the specific numbers of everything to explain it in terms of your specific setup.