But quite a few of the SD cards Galbraith tested in the 5D Mark III actually delivered very similar speeds.
There were two SD cards that delivered nearly identical performance: one was a Class 6, and one was a CLass 10 UHS-I SanDisk Extreme Pro-which should be capable of write speeds up to 95 MB/s.Īt first, it seems bad that a Class 6 card would be faster than a card claiming to deliver 95 MB/s speeds. However, the fastest-performing SD cards could only write at 18 or 19 MB/s. The fastest CompactFlash cards could write JPEGs at around 46 MB/s, and RAW files around 80 MB/s. Galbraith tested out the Canon 5D Mark III with a variety of CompactFlash and SD cards. A Slow SD Card Controller in a Camera: Canon 5D Mark III Here's an example. Next time you buy an SD card-or anything that uses one-keep in mind that hardware like the memory controller and CPU, even in a brand new camera, may dramatically undercut what the card should be able to deliver. I also looked at of SD and CompactFlash performance numbers. Last year, while researching SD cards for The Wirecutter, I talked to Nikon, SanDisk, and some photographers, including the experts at. Unfortunately, age isn't the only factor that accounts for SD controller performance. You're not going to come close to maxing out what the card is capable of. Using a really fast SD card with a slow host controller is a bit like plugging a USB 3.0 flash drive into a USB 1.0 port. For example, older host controllers only support the SD and SDHC formats, not the more recent SDXC. Devices like digital cameras talk to SD cards with host controllers, and those host controllers can vary in speed and compatibility. The speed of the card makes a difference, but a fast card isn't guaranteed to reach its potential in every device you use it in. Slap one of those cards, like the SanDisk Extreme Pro, into a camera, and you'll feel the difference-photos write to the card in a snap and reviewing a shot won't leave you staring at a blinking LED for three seconds. SD speed classes can be really confusing-Class 10 cards are technically the fastest, with required 10 MB/s minimum read and write speeds, but there's a world of difference between a basic Class 10 card and a Class 10 UHS card, which can operate at quadruple the standard SD clock speed. When shooting digital photographs, you can usually feel the difference between a cheap Class 4 SD card, with its minimum 4 MB/s write speeds, and a faster Class 10 or UHS (Ultra High Speed) card.