Reviewed in the United States on July 2, 2019
"1TB Micro SDXC Memory Cards" have been sold online for a handful of years now, by companies with strange, made-up-sounding names like Jojlon, Winston, or Krrttphfff. However, until the SanDisk 1TB Micro SD hit the market this year, every single one of those sellers advertising a 1TB Micro SD card were lying. If you read the comments section of those items (yes, you can still find the bogus, scamming, way-smaller-than-advertised micro SD cards being sold on this website TODAY!) you will see them filled with dissatisfied customers, claiming they were gypped and posting the screenshots of their benchmark software results to prove it. Now, because of this storied history of scammers specifically using this website, and other like it, claiming to sell high-capacity microSD cards, but in reality hocking crappy cards made in China that are, at best, 1/10th the size of what they claim to be, I suspect that a large numbers of the tech-oriented crowd will come across the item in question today: the SanDisk 1TB Extreme microSDKC UHS-I Memory Card (C10, U3, V30, 4K, A2... blah blah blah blah). If a significant percentage of the people who consider purchasing this item get cold feet and back out, due to the aforementioned rampant scamming occurring at the hands of sellers advertising *VERY* large capacity microSD cards, THAT WOULD BE A SHAME!
I had significant doubts about the product myself, due to my calculation that there was a high probability this was yet another scam by online rip-off artists. However, I reeeeeeally needed a microSD card bigger than 512GB, for my cell phone. I have juuust about 650GB of high-res music (a lot of DSD files, for example) which I like to carry around in my phone, and this meant that, for me, the highest-capacity-microsd card-available-to-date, the 512GB, simply wouldn't cut it. I saw the 1TB SanDisk appear on Amazon a week or so ago, but it was not yet available for purchase. Then, a few days ago it officially became available for purchase, and I immediately paid the $450 and, thanks to Prime, selected FREE One-Day Shipping for it.
The next day, after I received it in the mail, I immediately put it in the USB adapter it came with, plugged it in to a USB 3.0 slot on my laptop and oppened CrystalDiskMark6, followed by ATTO Disk Benchmark, and, one by one, tested the capabilities of this microSD card. The card's manufacturer claimed 160MB/s read speeds, and 90MB/s write speeds. I guessed the card would not live up to those claims, as in my experience cards almost never live up to their manufacturer's claims about their capabilities. So what were my results? You can check them out yourself from the pictures I uploaded.
First, the CrystalDiskMark6 tests:
At the 50MB size and 1GB size for the test file, for reading speed the card actually reached the manufacturer's stated speed (nearly), and then outperformed that speed on the second test, while on the writing test the card excelled above the manufacturer's advertised speeds. Specifically, during the Seq Q32T1 test, the card Read speed was 147.2MB/s and 166.1MB/s for the 50MiB and 1GiB test file sizes, respectively. The Write speed was 103.4MB/s and 104.6MB/s, respectively! That's a shock, for me, I was NOT expecting a card to actually live up to, and then SURPASS a manufacturers claims.
NOTE: the third CrystalDiskMark6 test results are much less impressive. "What happened there?" you might ask. Well, if you take a close look you'll see the test file size in that case is 32GB. Thats GIGABYTES. 32GB is the largest test file size the program can do, its maxed out at that point. Considering the mechanics of how microSD cards work, the concepts of allocation unit size, etc, its no surprise at all that the card failed to perform well with a test file size of 32GB. MicroSD cards were simply not meant to be used as devices with allocated unit sizes of such a significant size. Its an unrealistic and useless test, that does not help convey any relevant information about the product. I only included it to show the full range of test results obtained from both extremes and the average of the variables available for users of CrystalDiskMark6 to alter.
Second, the ATTO Disk Benchmark test results. Above I have listed sequentially the transfer rate results for the card with test file sizes of 64MB, then 128MB and 256MB, all expressed in bytes, and the transfer rate results for the card with test file sizes of 64MB, then 128MB and 256MB expressed as inputs and outputs. Again, we see that the card, at its best, is able to consistently reach Read speeds of approximately 160MB/s, and, I'm happy to report, Write speeds consistently touching 100MB/s! Or VERY close to it, anyways. The point is its significantly above the stated 90MB/s claimed by the manufacturer.
All in all, I'm happy. After testing the card and putting it through the proverbial wringer I feel it lives up to and surpasses my expectations in terms of its performance and capabilities. I have now put about 600GB of data, mostly music files, onto the cards and it works flawlessly so far. I have not yet had any issues with file corruption, and the item seems to be durably manufactured. It also comes with a free backup/rescue program download, called RescuePro Deluxe, so that's a nice addition.
TAKEAWAY: If you have the need for a microSD card larger than 512GB, and you can afford the $450 sticker price, GO FOR IT.
You can keep an eye on this review, if I have any problems with the card in the future I will add my critique at the bottom as an "EDIT:"