# Troubleshooting: USB 3.0 Speeds - Is it the card or the reader?



## acaurora (Aug 19, 2013)

Hi all,

So I have noticed this recurring issue with my cards. Currently I have 2 32GB Sandisk Extreme Pro CF cards and one 16GB Sandisk Extreme card. The Extreme Pros are 90MB/s advertised, and the Extreme is 45MB/s advertised for read speeds. Here is my problem:

Normally when I come back from taking pictures, I just tell Lightroom to directly import from the card and handle the file copying to my hard drive, etc. However recently I tried to manually copy the DCIM folder to my computer and noticed that while the initial speeds were fast (60+MB/s), after a while it would drop to 11-12 MB/s! It was a easy reproduced several times, in which for one of the 32GB cards once it had transferred 4 GB it would drop to the slower speed, and then for my other 32GB it would be 10GB before dropping. The 16GB Extreme did not exhibit this problem. Now here's the weird part: After it copied however many GB before switching, it would pause for a second or two before switching. And if I cancelled the copy, and then tried to copy another folder or restart the operation, it would stay "stuck" in that 11-12MB/s speed. The only way to fix it would be to unplug/replug back in the reader or the card. 

I am currently using a Sandisk ImageMate USB 3.0 All in One reader, and this reader with my cards was producing this issue. I had an older USB 2.0 version of the same reader, and it did not produce this issue (it stayed at about 22-25MB/s the whole time). 

I have tried this in Windows 7 using TeraCopy as well as in Windows 8 using the default file handler. 

To me it sounds like the reader's messed up, if the USB 2.0 reader is reading at a consistent (comparatively slow to the USB 3.0) 22-25MB/s for all 32GB. However the fact that the "limit" before it changes speed is different on both of the 32GB Extreme Pros and does not happen on the 16GB Extreme make me think its the cards. 

Does anyone else have any input or suggestions as to what is causing this?


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## alexanderferdinand (Aug 19, 2013)

Interesting.
I have a 32GB Sandisk, the 60MB/s- version. Does not slow down.
The Lexar 32 GB 1000x does slow down after, dont know exactly, the first third of the download.
Both with a Lexar USB 3.0 cardreader.
I'm curious too for some answers/theories.


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## Mt Spokane Photography (Aug 19, 2013)

Try another reader and / or another computer to find out. It can also can be usb 3 issues on the computer's usb 3 port.


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## PMacLeod (Aug 19, 2013)

Also, how full is your HD? Sometimes if you don't have enough free space the Lightroom direct import can slow down substantially. This is based on just my experience but it seems to be pretty consistent when I have less than, say, 15% free space.


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## Jim Saunders (Aug 19, 2013)

Have a look at the other USB devices you have connected; My cellphone for instance causes some screwiness when I have it plugged in.

Jim


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## ecka (Aug 19, 2013)

1st. Win7 has a silly way to calculate file transferring speed. It shows the progress of data migration to memory buffer instead of the final destination.
2nd. This bug is very obvious with larger files when the source drive has faster copying speed than writing speed of the destination drive, it hangs at 99% (or before finishing each file in a sequence) while waiting for data to finish writing from memory buffer.
3rd.


Jim Saunders said:


> Have a look at the other USB devices you have connected; My cellphone for instance causes some screwiness when I have it plugged in.
> 
> Jim


Some USB devices do not "play nice" with others, you better not use them simultaneously, specially on the same USB hub.

4th. Try copying to a different hard drive (not sure about 11-12MB/s, but if the one you are using is near full it's writing speed may drop below 30MB/s) or using a different USB 3.0 reader.


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## acaurora (Aug 19, 2013)

Thanks for the suggestions guys... I have tried all of those options. Different computer, using different destination hard drives. The destination hard drives are not full, and I'm not running any intensive programs at the same time. I have tried with Windows 7 and Windows 8 (on different machines) on different USB ports with the same results.

I have ordered the Lexar USB 3.0 reader and hopefully when that comes in may shed some light on what the cause is.


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## ecka (Aug 19, 2013)

I'm using Transcend USB 3.0 reader and it gives me all the speeds they claim on each card (like ~80MB/s UHS-1). It is cheap, small and it works. If someone is interested, model number TS-RDF8K


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## Drizzt321 (Aug 19, 2013)

Lexar actually had a firmware update for their card reader at one point, and my speeds increased dramatically. Maybe check if your old reader has an update?


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## acaurora (Aug 19, 2013)

So I checked for an update, and there was. However, that did not resolve the issue. Instead, now it will pause every 10 seconds for about 5 seconds. The performance is now worse.


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## DigiAngel (Aug 19, 2013)

I have that Sandisk one too, does around 125mb/s with my not-so-special Transcend 400x Cards (yes i also benchmarked using Atto and so on, they are faster then the 90mb/s advertised) - as far as my Harddisks are able to keep up there is no drop in speed even after copying 30gb+.


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