[UPDATE: If a search engine has brought you here, I found an error in my testing – a quick scan might be useful here, but the final information is found in the “oops!” update.
I recently posted about the benefits of “X’s” – one measure for measuring the performance of our digital film cards, both SDHC and Compact Flash.
Now that I have the 1000X Lexar Professional Compact Flash cards in-hand to go along with my 400X Lexar Professional SD cards and both USB 2.0 and 3.0 card readers, I figured I’d test the combinations and see how things turned out. The results were surprising…
Here was my methodology: I had 2.03GB of JPEG files from shooting the day before. I would attach the reader with the card and dragged the DCIM folder from the card to a new folder on the drive. I timed it from the moment I released the mouse button until the moment the copy window disappeared. After each test, I deleted the folder so the same amount of space remained on my hard drive, which is a 180GB SSD (which is pretty fast, so your times might vary on spinning hard drives).
First up were the cards on the USB 3.0 reader, a Kingston model with good reviews on Amazon, though sometimes I wish I’d bought the Lexar version, which looks smaller and is less cluttered with other card types I don’t care about. The 400X SD card finished copying in 2:05.4, where the 1000X Compact Flash card took only 1:09.1, not quite twice as fast.
Next I plugged in the much older USB 2.0 reader, which was also a Kingston product. I bought the USB 3 reader when I thought one of my kids had lost this one. Since I knew I was soon getting a ThinkPad T430s with USB 3.0, I went ahead and got the latest thing. Then my wife found the old reader. Oh well, at least I have my own now.
Anyway, after running the tests, I was a little dumbfounded. The SD card took 2:31.8, which gives USB 3.0 a decent 26 second advantage. Since this was only 1/8 of the card capacity, that can really add up. However, the 1000X card finished in 1:10.7, giving USB 3 a modest 1.6 second advantage.
I heard back from Lexar when I asked about incompatibility issues, and their reply was they were maintaining compatibility and would work with any customers experiencing issues., so I guess this is good news for people with USB 2.0 readers and PC’s with USB only 2.0 slots. At some point I’ll try to re-run these tests on a USB 2.0-based machine.
The last test surprised me quite a bit. I copied the same files from the SD card using my built-in SD card reader on my machine. The 400X SD card was exactly ten seconds faster than the 1000X Compact Flash card!
I’m sure someone can explain the reasons why, but the lesson I take away from it is this: just like all cards at the same rated speed don’t deliver the same performance, overall performance isn’t limited to the card. Your reader makes and the machine itself can make a big difference, too…
Knowing what I know now, I’d probably buy 600X SD cards and slower Compact Flash cards as backup – my goal in buying 1000X cards (which are not-quite-twice the price of the 400X cards) was to get faster transfers off the cards. My guess is 600X cards off the built-in reader would be faster than the 1000X cards for about half the price.
If your PC doesn’t have a built-in reader, the faster CF cards give you a big benefit, but if you do, the SD cards might be a faster an more affordable alternative…