Diagnosing slow external card reader

[Puffhead]

Hi guys!

 

I bought a Delkin USB 3.2 CFExpress card reader (DDREADER54) and a Sony 128GB Tough CFexpress card (CEBG128/J) for a Nikon Z6. I'm seeing speeds capped at about ~45MB/s copying data from the card to three different computers (all SSDs), with all different types of cables using the card reader listed previously.

 

Is there something I don't know about CFexpress or Type-c that I'm missing here, or does there seem to be an issue with my card reader? I can shoot plenty of images in a row before the buffer on the z6 fills up, so im assuming its the reader and not the card.

 

Here's what computer/cable combos I've tested so far.

 

2019 XPS 15:

Included type C cable to type C port: doesn't work

Own type C cable to type C port: 40MB/s

Included USB cable, left port: 40MB/s

Included USB cable, right port: 40MB/s

Oneplus type-c cable to type c port: 40MB/s

USB3 SD card reader with 130MB/s SD card in it: 90MB/s

 

Intel NUC:

Included USB cable: 40MB/s

 

9900k/MSI z360 Tomahawk:

Included USB cable into 10GB USB port: 40MB/s

Included type c: doesn't work

Own type c to type-c cable: 40MB/s

 

I just downloaded Ubutnu 20.04.1, a 2GB ISO file.

Copied it from an the Internal SSD on my XPS 15 to the CFExpress card, and it transferred at 40MB/s. I then copied it back to my computer and it was still capped at just above 40MB/s.

[Bombastinator]

There are several points of possible slowdown

1: the card itself.  Various card types transfer data at different speeds.  They vary widely.  Long ago “10x” was advertised meaning there were cards that were 10x slower.  That was long ago though. Some have likely gotten faster.  My memory was speed of transfer had a lot to do with price.

2: the reader. There may be a cap there

3: the port used.  Not all usb is created equal. Just because you have a 3.2 cable doesn’t mean you have a 3.2 port.

[Puffhead]

47 minutes ago, Bombastinator said:

There are several points of possible slowdown

1: the card itself.  Various card types transfer data at different speeds.  They vary widely.  Long ago “10x” was advertised meaning there were cards that were 10x slower.  That was long ago though. Some have likely gotten faster.  My memory was speed of transfer had a lot to do with price.

2: the reader. There may be a cap there

3: the port used.  Not all usb is created equal. Just because you have a 3.2 cable doesn’t mean you have a 3.2 port.

The CFExpress card advertises peak reads of 1700MB/s, and writes of 1480MB/s.

 

The reader is "USB 3.2 Gen 2 Type-C Interface (10 Gb/s)"

 

All regular USB ports on the 3 computers while using a USB 3.0 SD card reader and 95MB/s SD card copy to the computers at 90MB/s. These are the same ports that are moving at 40MB/s with the CFexpress reader and card.