USB Transfer Speed

ThatDiabeticGuy · August 27, 2023

I’ve been having some annoyances with USB transfer speeds and bottlenecks.

I’m a videographer and every time I have to offload and backup my footage it’s a pain. I always backup to 3 drives but I feel like I’m constantly running into bottlenecks. My SD cards max out at 250MB/s, my card reader is USB 3.2 gen 2x2 plugged into a correlating port, drive 1 is an internal NVME, drive 2 is an external SanDisk Extreme Pro, and drive 3 is my NAS which is connected via 1 gig Ethernet (that’s a bottleneck I’m aware of).

when backing up files I will transfer from the SD card to all 3 drives simultaneously. In my mind that should mean that I’m getting around 250MB/s on drives 1 and 2, and around 100MB/s on drive 3. However, I usually get about 65 to 100MB/s on all three drives.

Is there a reason the speed is so bottlenecked? And is there anything I can do to solve it?

FloRolf · August 27, 2023

Well it's pretty simple, the SD card doesn't know it has to copy all the same files to different locations, so it has to make 3 different copies, basically cutting your speeds into 1/3.

Would be better to Copy to the PC and from there to the NAS and External disc simultaneously.

EDIT: You can also use Robocopy, that could speed up copying because it is multi threaded while windows copy is not. I am assuming you copy hundres of files only a few MB in size.

ThatDiabeticGuy · August 29, 2023

On 8/27/2023 at 3:49 PM, FloRolf said:

Well it's pretty simple, the SD card doesn't know it has to copy all the same files to different locations, so it has to make 3 different copies, basically cutting your speeds into 1/3.

Would be better to Copy to the PC and from there to the NAS and External disc simultaneously.

EDIT: You can also use Robocopy, that could speed up copying because it is multi threaded while windows copy is not. I am assuming you copy hundres of files only a few MB in size.

Unfortunately I have to copy from the SD card each time to fight file corruption. If a file was corrupted while transferring to drive 1 and then I copied that file onto drives 2 and 3 the file would be corrupted on all three drives. But if I copy fresh from the SD card each time that risk is lessened.

How does Robocopy work and where can I find it? My files are usually between 350MB and 3GB per file. And I’m shooting about 150GB at most on one card.