Why is USB data transfer to an onboard sd card so slow?

[Rod_]

I mounted a SanDisk Extreme Pro memory card in the Xperia 5 and I bought a new USB 3.1 gen 2 compatible USB C to USB C lead and connected it to a brand new Dell 7000 laptop with a gen 9 Core i7 processor, 16Gb of RAM and a Thunderbolt port that should have been more than capable of very fast transfers on to the USB 3.1 compatible cable and phone.

I connected the phone and started to transfer some folders of pics, vids, music and comics. It was as slow as waiting for poo to slide down the inside neck of a wine bottle (slight exaggeration but only slight). For about 8gb of stuff, the computer's dialogue box gave an estimated completion time of over a day!

It wasn't the computer's usual dialogue box (the one that shows you the graph, etc). It was a much simpler looking box. I take it that was because, in the phone's 'USB Preference' settings, it was checked, by default, for 'This Device' (the phone) to control the USB port. So I cancelled the extremely slow data transfer and tried to change the USB control preference to 'Connected Device', in the hope that the laptop could take control of it's own USB port and start a decent data transfer (and maybe show the familiar kind of Windows data transfer, dialogue box) . After a brief 'progress swirl' while it tried to change over it just said 'Couldn't change'. Why offer the option, then?!

I had to remove the memory card from the phone, stick it in a tiny Kingston USB 2 card reader that I have and the transfer is going at about 16Mbps, with a completion estimate of 40 minutes.

It's a sad day when Sony's newest 'USB 3.1 compatible' premium smartphone can't do a job (load about 8 Gig of stuff on to SanDisk's top of the range SD card) in less than a day, when a cheap USB 2 card reader can do it 40 minutes!

Anybody know of anything I can do or change to get it to work like it probably should? Or was it busy uploading all of my data to a cloud, or something, while I was doing the transfer?

I'm really not all that impressed with the phone, either. It's got a good screen and speakers for Netflix but it won't even Bluetooth to my car audio system either (Sony blame Google for that) and I would never have believed that my old ZTE Axon 7 would have had better connectivity performance with Bluetooth and over USB, than if I went back to a Sony and spent over £500.

[RottenFoxBreath]

Can't help with your speed issues, apart from I bet it's driver related 

As to the car Bluetooth, if you enable developer options, go in to them, you can pick another Bluetooth version by scrolling down to networking, then you can pick another Bluetooth avrcp version.

I bet your car isn't compatible with the latest so you will have to pick 1.4 or 1.5.

[Yekollu]

USB Transfer works fine for. Did you try with a different cable and different SD card?

[Ghirst]

Thank you for your response about the bluetooth settings. This has helped me so much, I was considering sending the phone back!

[hägar]

I am a little bit confused about your description.

Did you transfer the files to the internal storage of the phone or to the standalone sdcard?

What happens if you try to copy files to the device with the sd-card ejected?

Just to make sure to rule out different fault options, perhaps you should try to:

* Remove sdcard and try to copy files to the internal memory of the device.

* Try with another usb cable

* Try another port of the computer

Are you using the cable shipped with the device, some usb3/usb-c cables are crap 😕