I measured with different software (CrystalDisk Mark, Atto), I get a speed reading of 43 MB / s max (of course be careful that your SD card reader are correctly connected to a USB 3.0 port (not USB 2.0) for such flows.
BUT write, the card does not exceed the 14 MB / s.
So unlike the above models (type Sandisk Extreme), the write speed is different than in reading.
I already knew at the time of purchase. So no surprise about it. But it is important to know this if you plan to buy such a card.
In contrast, even when I put 4 stars is that this card, yet type of SDXC 64GB is recognized by my old Nikon D90 camera while it was supposed to accept only SDHC 32GB max . So rather positively surprised by this. No worries about the burst mode in 7img / s, RAW + JPG, but the D90 is 12MP images. So the 14 MB / s write can become limiting to other cameras with a burst mode higher and with more pixels. After also distrust on flows. For it often happens that the SD card reader integrated cameras is internally wired USB 2.0. So real flow max 30MB / s. And suddenly, SD cards Far type with speeds of 60 MB / s can bring nothing in this case. I refer you to this YouTube video that explains this problem well: [...]
Then I also use this card Sandisk Ultra 64GB (40MB / s) on a Sony camcorder PJ650VE, full HD, max quality.
And any problems.
And even in the photo mode camcorder, reactivity is much more present (less than 1 second to save the photo) with an SD card Sandisk Extreme (32GB) with which I do not know why, pictures taken with the camcorder take longer than 3-4 s to be saved while this Sandisk 32GB Extreme has write speed more than double compared to the Ultra model. Is a compatibility problem with the UHS Mode? (Clearly stated on the 32GB Extreme unlike Ultra 64GB)
As for video recording in full HD (1080p, 50Hz, H264, max quality 28Mb / s), no problem.
So finally, given its price, rather satisfied for now.
After you have to see its longevity.
For now, I only use it for one week.
Too early to tell.
FYI also, this Sandisk Ultra 64GB card is also compatible with the external hard drive WD My Passport 1TB Wireless that includes a SD card reader. However, it will be trèèèèss patient for a copy of the SD to the hard disk, especially given the size of the SD (over 2H to copy 64 GB). But this is not a problem related to SD (same problem with other SD). This is due to the WD drive (future correction? Via firmware?).
Finally, I bought this card Sandisk Ultra 64GB version "Frustration-Free Packaging".
For information, it is delivered in a cardboard envelope, without the little plastic box for storage.
Just a paper detailing the warranty, in addition to the SD card.
