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  • Stable and high writing speed

  • Durable construction

  • Price compared to CFexpress


  • Reading speed fluctuates

Do you need a reliable memory card for professional photography? Or a card with fast and stable recording for high-quality video recording? The SanDisk Extreme Pro series brings both in one body, specifically here we are testing an SDXC card with a capacity of 64 GB with a Sandisk Extreme PRO UHS-II card reader.

The SanDisk Extreme Pro 64 GB memory card is really fast, in practice it even exceeded the write speed declared in the specifications. It is therefore suitable for high-quality video and at the same time provides a stable recording so that there are no errors. It will also please photographers focusing on action interests, as it can also handle fast continuous shooting. The only drawback is the read speed, which starts to fluctuate after writing 10 GB of data.

The card is of the UHS-II type, which means it has two rows of contacts instead of one row on slower cards. However, this does not prevent backwards compatibility, it just means that maximum speeds will not be achieved in such cases.

Recording speed and stability

Each memory card has several certifications regarding their speeds, here we find reading up to 300 MB/s, writing 260 MB/s, UHS-II, U3, V90 or Class 10. However, this did not prevent me from pushing the card to even higher extremes . I had the opportunity to test it together with the very fast and video-centric Lumix GH6, which smartly enables and disables different video qualities depending on the storage medium, and here it shone as the best option with a data flow of 300 MB/s, i.e. 40 MB/s more than the paper assumptions .

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It was a video with a resolution of 5728 x 3024 px at 50p and a total data rate of 293 MB/s, I tried both the smoothness and the stability test and the card handled such a high data rate without any problems. That 300 MB/s is the ceiling for the SD format today, so you’ll reach the maximum with this model. If you need higher data streams, you have to reach for more expensive formats such as CFexpress or CFast. However, such storage media are many times more expensive than SD.

In the quick shooting test, I shot a burst of 200 photos saved in RAW plus JPEG for a total size of 11.4 GB in about 12 seconds. Storing such a large amount of data should theoretically take 38 seconds, which was also reflected in practice. The camera was still saving tens of seconds after the photo was taken. However, the key is that there was no error that caused the shooting to be interrupted or a write error. I’ve tried other bursts of quick shots and haven’t had a single problem.

Reading speed and stability

When connected to a computer, data is copied at a speed of 270 MB/s using the SanDisk Extreme PRO UHS-II fast reader. However, if you’re copying more data, after about 10 GB of data transfer, the transfer speed starts to fluctuate significantly, dropping to half of the maximum speed on average. This happens with both large and small files.

In comparison, there is no drop in speed when copying the same data from the computer to the card. In any case, the drop to around 150 MB/s when reading is not significant, it is still faster than when reading UHS-I memory cards.

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I also had the card tested with CrystalDiskMark (v8), this benchmark confirms a maximum sequential reading of over 300 MB/s and a maximum write speed just below the indicated 260 MB/s, although in practice I reached higher values.


In practice, this is a very reliable memory card that will be appreciated by videographers rather than photographers. It can record high-quality video with a data rate of up to 300 MB/s, which is more than the advertised value. It makes sense for photographers, for example, when shooting sports, where you need to take a lot of pictures in quick succession and be immediately ready to take the next series.

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A fast reader like this SanDisk Extreme PRO UHS-II is also suitable for a fast memory card

The big advantage of SD cards is their price, the CFexpress format will offer twice the writing speed at twice the price, if we compare the 64GB variants. That’s not enough, and SD cards are becoming more and more versatile, so they can be used in more (non-professional) devices. So if you’re looking for the fastest SD card possible, the SanDisk Extreme Pro 64GB is a great solution.


  • Type: SDXC
  • Interface: UHS-II and U3
  • Capacity: 64 GB
  • Read speed: 300 MB/s
  • Write speed: 260 MB/s
  • Durable construction
  • Video class: V90
  • Price: 2,300 CZK

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