I just received a 64GB SDXC 400x for my X-Pro 1 and put it into my MBP tonight to transfer photos. I had 4.77GB worth of photos and it was much slower than the PNY SDHC card that's in my wife's NEX-5N. That card is only rated to read at 35MB/s but it reads close to 50MB/s according to my benchmarks. The Lexar 400x is only reading and writing at 20MB/s. This is my first SDXC, am I missing something? I know my MBP only supports USB 2.0 but that tops out at 60MB/s and there's nothing else on the USB controller.

I put it in my wife's 2012 MBA and it hit 30MB/s read and 37MB/s writes. This seems pathetic, hopefully I'm missing something about SDXC, but from my understanding it simply refers to extra capacity and has to use a file system supporting 32GB+ in storage.

Thanks for those who help.

I threw it into my old Core 2 Quad server and it hits 19.2MB/s Read/Write. I'm really hoping that someone can offer insight, I'd hate to return this only to discover that it was an issue on my end with incompatible hardware. I would expect speeds close to 60MB/s on my wife's MBA since it's newer, but maybe my expectations are too high for a premium product.

Thanks

Usually these cards offer some minimum speeds. More often than not they're limited by they computer/speed of the connection their being transferred on. Also if you have the time to test the card writing on 3 different computers. How do you not have an extra 5 minutes to wait for the card to write.

I work in IT and the benchmarking tools are already on my systems. I paid more money for a card that is advertised at 60MB/s reads. This card is not measuring up and I'm not wasting money on a product that is either falsely advertised or defective. Rather than being smug about it I decided to post a question in a forum where we should be helping each other.

Any chance that the issue is related to your benchmarking software, and not the card its self? Try putting a bunch of photos on the card, and then time a "manual" benchmark to transfer the files the way you normally would. You should be able to do a rough transfer timing to validate or refute what your benchmark tool is telling you.

Thanks for your response Ronald. I have verified the speeds with set transfer rates from the card to the PC. Windows reports reads at approximately 20MB/s. My PC actually uses a different piece of software called HD Tune to perform the test. One thing I find odd is that when I first insert the Lexar into my Mac I have to wait on the spinning pinwheel for a while. I don't get that issue with the PNY 32GB SDHC. As for write speeds, 20MB/s is spot on with what the cards rated at. I'm beginning to think that it's a defective card. Users on Amazon have reported much higher transfer rates than I am getting.

My philosophy about all this is that high-speed cards are MAINLY for the benefit of the shooting-- buffer empties faster, longer burst, faster chimping, etc.

That's what I'm paying for at least.

That said, if this is a UHS-I card (http://en.wikipedia.org/wiki/Secure_Digital#UHS_Speed_Class)-- you're not going to get the rated speeds unless the device it is in also supports UHS-1. Do your computers?

Essentially, this has nothing to do with the card, it has to do with the reading device. Sure USB 2.0 can support the speeds you want, but if the reader doesn't support UHS... you're out of luck.

AFAIK... your computers simply don't have UHS-1 compatible readers.

justruss thank you for your responses. I believe you hit the nail on the head. Reading around and researching UHS-I on the Macbook led me to an Anandtech article. To sum it up, a UHS-I card had 40MB/s read on a MBA and 80MB/s on a MBPR model. I got 37MB/s on my wife's MBA so it makes sense that my early 2011 MBP doesn't handle UHS-I well. The sad thing is that I notice faster write speeds on the camera, but I really wish it dumped to my PC faster. Perhaps I'll pickup a reader that is UHS-I compatible for my server.

Thanks again for helping me understand!

http://www.anandtech.com/show/6063/macbook-air-13inch-mid-2012-review/2

The SD card reader on the 13-inch MacBook Pro had no compatibility issues with Patriot's EP Pro UHS-I SD card. Max performance of the reader appears to be capped at 40MB/s however:
The rMBP by comparison can deliver more than 80MB/s in the read portion of this test. Even writes are faster at ~40MB/s on the rMBP compared to around 32MB/s here. It's a lot of these little things that contribute to the differences between Apple's MacBook Air and Pro lines.

No problem!

You should still see the most important benefit-- in speeding up shooting.