64GB SDXC Class 10 UHS-1 R40 Memory Card (SF64UY/TQMN) (OLD MODEL)

I posted this about the Transcend 32 GB SDHC card that was getting trashed in reviews by Canon owners. It also applies to the Sony card (read down), and readers may find it helpful in evaluating SD cards in general.The 1-star threads on the Transcend are like watching a committee of blind men describing an elephant. Unsurprisingly, no one has the complete picture, but a lot of Canon owners think these cards are bogus. SD card technology is very complex, the Class system is often misunderstood, and there is a long history of compromised cards appearing on eBay -- or even from reputable dealers who have been hoodwinked. Kingston cards are most often faked (or taken from the midnight production run); that's because Kingston has about a third of the flash card market and doesn't forge their own chips, but any manufacturer can be spoofed. It doesn't pay to buy cheap cards on eBay or less reputable sources.An SD card contains a controller chip and flash memory chips, even the microSD versions. Realize that SD means Secure Digital, and that security comes from crypto managed by the controller (MMC cards didn't have that bloat, but Hollywood DRM requirements made sure they faded). The controller can be pretty powerful: the Samsung SD controller is a 32-bit ARM TDMI chip with 128 k of code space -- that's cell phone power. It handles I/O and fading (when the card slowly wears out its NAND sites after about 100,000 hits so writing is randomly distributed and kept track of), the factory self-test, and a host of other functions, but it can also be programmed to report a false storage capacity. Sometimes the firmware on the controller or its crypto or something else on certain cards leads to problems with certain hardware, as it has, for example, with the Samsung Galaxy III and maybe the Canon cameras. Usually the card is found to confirm to SDcard dot Org specifications and the hardware is to blame, but you never know.To test the actual capacity of your card, use H2testw, which is free. It writes the full amount of data to the card and then reads it back (this nukes whatever was on the card). This can take more than an hour with a 32 GB card but it tells you if the card indeed holds 32 GB or if it has problems. H2testw also gives you read and write speed numbers, but it's unclear whether the numbers are for random read/write, or sequential read/write or a mix. Sequential write is what photographers and videographers most care about.Sometimes a Class 6 card might appear to test faster than a Class 10 card, when using computer read/write tests or even in a camera that wasn't designed with higher capacity cards in mind. That's because such cards use smaller block sizes (there's no cache on an SD card). Explaining the significance of this is getting too far into the weeds for an Amazon review, and modern devices and their firmware should not have that limitation.To test random and sequential read/write speed, use CrystalDiskMark, also free. Run the full suite; it won't take long. CrystalDiskMark requires that the card be formatted, and the most reliable way to do that is to use the free tool from sdcard dot org. A 32 GB card will may report 39.9 GB before formatting and 29.8 GB after; don't worry, you haven't been ripped off.Unfortunately, there's no easy way to read the manufacturer's ID off the SD card, even in Linux, to determine who actually made the card, because you have to have the card connected directly to a motherboard; an SD-to-USB adapter won't work because it doesn't pass through disk data, and that's what's in nearly all computers. But what do you care, so long as the card's as big and fast as claimed?Now, what about the Transcend 32 GB SDHC C10 card? Here are full test results from CrystalDiskMark:Transcend 32 GB SDHC C10-----------------------------------------------------------------------CrystalDiskMark 3.0.2 (C) 2007-2013 hiyohiyoCrystal Dew World : [...]-----------------------------------------------------------------------* MB/s = 1,000,000 byte/s [SATA/300 = 300,000,000 byte/s]Sequential Read : 19.953 MB/sSequential Write : 13.786 MB/sRandom Read 512KB : 19.618 MB/sRandom Write 512KB : 13.827 MB/sRandom Read 4KB (QD=1) : 3.003 MB/s [ 733.2 IOPS]Random Write 4KB (QD=1) : 1.414 MB/s [ 345.1 IOPS]Random Read 4KB (QD=32) : 3.491 MB/s [ 852.3 IOPS]Random Write 4KB (QD=32) : 1.842 MB/s [ 449.8 IOPS]Test : 50 MB [F: 0.0% (0.0/29.3 GB)] (x5)Date : 2013/05/12 18:19:47So you can see that the sequential write speed, what matters to a photographer or videographer, is over 13 MB/s, more than 30% above the C10 spec. The other speeds aren't too shabby, either. There's no way that this card is too slow for a contemporary camera, still or video, that is functioning and designed properly.Also on Amazon for a very attractive price is a Sony 32 MB SD card. Here are the full CrystalDiskMark test results for it:Sony 32 GB SDHS USH-ISequential Read : 19.998 MB/sSequential Write : 14.115 MB/sRandom Read 512KB : 19.772 MB/sRandom Write 512KB : 13.173 MB/sRandom Read 4KB (QD=1) : 3.682 MB/s [ 899.0 IOPS]Random Write 4KB (QD=1) : 2.302 MB/s [ 561.9 IOPS]Random Read 4KB (QD=32) : 4.517 MB/s [ 1102.8 IOPS]Random Write 4KB (QD=32) : 2.323 MB/s [ 567.0 IOPS]So the Sony is slightly faster, 40% over spec, on its sequential write. H2testw also reported full capacity and no errors for this card, so they are both top notch (The Sony doesn't come with a little case and the case for the Transcend case is about twice as big as it needs to be and so won't fit in the little pockets in a modern camera bag. Big deals.)Just for reference, here are the results for a contemporary USB thumb drive:SanDisk Ultra 32 GB USB thumb driveSequential Read : 22.508 MB/sSequential Write : 7.985 MB/sRandom Read 512KB : 22.365 MB/sRandom Write 512KB : 1.767 MB/sRandom Read 4KB (QD=1) : 3.719 MB/s [ 908.1 IOPS]Random Write 4KB (QD=1) : 0.520 MB/s [ 126.9 IOPS]Random Read 4KB (QD=32) : 3.871 MB/s [ 945.0 IOPS]Random Write 4KB (QD=32) : 0.482 MB/s [ 117.7 IOPS]As you can see, this USB drive is faster than the SD cards for reading, such as for playing music, running software, or looking up data, which shows that it is nicely optimized for its intended functions.As an aside, anyone who thinks they have lost data on an SD card can recover pictures using the free tool at z-a-recovery or recover everything(!) with the free PhotoRec tools.So, if people want to whine about these SD cards in their particular cameras, they should run these simple, free tests and reach their own conclusions about whether the cards are "too slow." The cards test above spec objectively. And they both work flawlessly on my still (not Canon) and video cameras. I think they have gotten a bad rap on Amazon from people who don't have the full picture, so to speak.I've also posted this as a review on the Transcend 32 GB page. I hope you found it informative.

Excellent

This is an SDXC memory card. It can only be formatted in exFAT or NTFS. These two format modes do not have a file size restriction. Any storage device that is 64GB or larger must be formatted in exFAT or NTFS. This is a reliable and safe card to store your files.This is important because not all recording devices will break up files into more manageable file size. All GoPro cameras will break up the files into more manageable sizes. Why? Suppose you record an activity that cannot be replicated. Suppose you fly four hours across country, drive another two hours to your destination. Then you're off shore fishing, or hiking a very scenic in area. If your recording device does not break recording into smaller files while recording there is the possibility that the single very large file could become corrupt and you've lost all the video for that expensive and long trip.If the files were broken down into smaller files and at the end of the hike or fishing tip and if one or two of those files were unreadable you'd still have the remaining files that you can stitch a decent video together.On devices that won't break down a recorded event into smaller files, a smaller SD card would be necessary for they can be formatted in FAT32 which is native to nearly all recording devices. The largest file size that can be recorded in FAT32 is 4GB..I have experience that occurred a few months ago during a trip to Zion National Park. I recorded several hikes with a Hero 5. I downloaded all the videos to a laptop and was not able to do any post-production work until after I returned home. Our days were so filled with activities there was only time to download the files to ensure enough room on Micro SD card. During post production there were two files out of the 10 that was created on the Angels Landing hike. Those two files could not be ready on any devices I own. I was able to create a complete video based on the remaining files. The story that I was trying to tell was incomplete due to the corrupted files.Imagine how I would have felt the recording device created one huge file and it was corrupted. I'd have the memory in my mind but not anywhere else.On other devices it is easy to pause and restart a recording. That action will create a new file each time. However, depending on the activity you may not have hands free to stop and start a recording. On the Angels Landing hike I used the elastic head mount for the GoPro and both hands to make the climb.