SD card write speed comparison

Gear

SD Cards

1. SanDisk Extreme Pro 32GB 95 MB/s
2. SanDisk Ultra 64GB 40 MB/s
3. Transcend 32GB 30 MB/s
4. #1 but with duplication on (writes to both cards simultaneously)
5. #2 but with duplication on
6. #3 but with duplication on

Camera

• Nikon D7000

Test

• Number of shots in 30 seconds when shutter is held depressed in high-speed mode
• All testing done with newly formatted cards

Result

1. 47 shots
2. 46 shots
3. 24 shots
4. 35 shots
5. 27 shots
6. 18 shots

The 40 MB/s card is likely writing to disk fast enough that it isn't filling the camera buffer, which makes it look identical to the 95 MB/s over 30 seconds without duplication. A longer test would likely reveal a difference.