Today I upgraded to a new USB 3.0 CF Card reader (Sandisk Imagemate), and found file transfers far faster than my old USB 2.0 model. Despite using CF cards daily as part of my work, I have never been particularly bothered by file transfer speed, but thought I would treat myself to faster transfers.
So I tested the transfer of 688 images totalling 22.7GB, and using robocopy I copied all images to the local M.2 drive on my laptop. I wrote a powershell script that starts a timer before running the copy, and reports the total elapsed time at the end. Also robocopy itself provides a useful summary once finished.
Here's the card I was using:
And here's the result:
This vastly exceeds the quoted theoretical maximums for that particular model of compact flash card, which according to most reports online are around 60MB/s.
In posting here, I am hoping to learn;
a) What the "400x" label on the card refers to specifically?
b) In what way I have failed to understand the basics of file transfer speeds OR how it is possible that the memory card I have here is approximately 2x faster than it should be.
Incidentally, I also bought some new CF cards. I went with 64GB Sandisk as they were very cheap. The new card does not have a "400x" or similar marking, instead it says "160MB/s" which I understand refers to the read speed. Nevertheless I am getting a consistently LOWER read speed with this new Sandisk card (as compared with my aged Transcend), which indicates to me that the new card does not perform as well, or at the very least, that the read speeds are near enough the same and there is a bottleneck elsewhere preventing higher transfer speeds. As a guide, the new Sandisk CF card takes approx 10-15 seconds more to do this transfer. I have tested this about three times.
Bonus question: c) Where could this bottleneck be? I am running a Dell XPS 9700, 32GB RAM, Dell OEM M.2 1TB SSD, and the Sandisk CF card reader (Imagemate) plugged in directly to the USB-C port of the laptop. Using the provided micro USB 3.0 cable. I have quiesced the majority of Windows services, especially file sync services, closed Dropbox/OneDrive etc., and closed the vast majority of applications that could be taking up CPU cycles. Is there something in the spec of the laptop I have that could be preventing getting near the quoted 160MB/s transfer speeds of this new CF card?
** It may be tempting to suggest here that CF cards are obsolete and I shouldn't use them. Please understand that whilst they are technically inferior to other formats, many people continue to use them due to their robustness in the field. When shooting photography I use dual cards (CF and SD), writing to both simultaneously.
