Quick Review: Sandisk Ultra 128Gb UHS-I microSDXC Card

I was pretty disappointed to have been dudded in my first attempt to get a hold of a 128Gb microSDXC card, but I won’t let an eBay fake stop me. After all, Sandisk products are supposed to be high quality. This time, I decided to high-tail it to a brick-and-mortar store (ARC Computers) to grab one from the shelf for AU$121.26 – and managed to grab the only one. This also provides a solid set of comparison images for direct comparison in case there is doubt.


Despite the item listing at ARC claiming to have 30Mb/s read speed, it seems that the cards that were stocked are the updated version of the package, now claiming up to 48Mb/s.


Specifically, it is noted that the tray and card sits neatly in its cutout, the printing is sharp and the colours aren’t oversaturated. The reflection in the phone screen is fine, the centering of the logo is good. The hanger-tag cut-out is the special “squared off” version rather than a generic hanger cut-out. Everything’s all good so far.


The rear seems to have a new re-designed printing with significant reduction in printed text by the removal of other languages. This is probably because this packaging is specific to Australia and New Zealand market. Important is to note that there is no inconsistencies in the use of the SDXC logo – you won’t find any SDHC logo hiding here.


The package also feels a little different – this is because there’s an electronic article-surveillance tag (metal strip acousto-magnetic/sensormatic type) pre-installed in the package. This can make for a difficult experience sliding the card carrier out.


The card carrier has a very large area at the top, where a specific warranty statement for Australia and New Zealand is provided. The package also extends significantly left and right of the cut-out as well so there’s little chance of popping it out.


The card itself is directly printed upon and is solid edge to edge. No signs of white edges or remarking should be apparent.


The rear contacts are nice and clean, with a green PCB substrate (which is very similar to their Sandisk 32Gb Extreme card) along with place of manufacturing markings on a black painted area.

DSC_9782 DSC_9783

The adapter is also up to the quality expected – straight pins, laser etched date and place of manufacture at the back, and “rails” to guide the card into the adapter. There really isn’t any doubt about the authenticity of this product at this stage.

The read-out of the card’s characteristics are as follows:

Capacity: 127,864,930,304 bytes
CID: 035344534c31323880504583a700ea5f
CSD: 400e00325b590003b8aa7f800a40400d

The vendor ID code of 03 matches the expectation for Sandisk products.

Performance Test

Unlike the former Ultra products which only claimed up to 30Mb/s (which was actually conservative), this one claims 48Mb/s. Lets see if it’s actually capable of reaching this mark.

HDTune Pro with Transcend RDF8


Reading with the RDF8 fell short of the 48Mb/s claimed on the packet, averaging 42Mb/s. This is, however, in the ballpark of what the Ultra cards have performed in past testing, and is still miles faster than the counterfeit stuff.

HDTune Pro with Kogan RTS5301


No compatibility issues were had with the card in the Realtek RTS5301 reader (which is often picky about which cards will run at UHS-I). The average read speed is faster, at 43.9Mb/s, still a little short of the claimed “up to” speed.

CrystalDiskMark with Transcend RDF8


The card seems to put out relatively expected speeds for an Ultra product, noting that the sequential write performance is actually pretty good for a Class 10-rated Ultra card. The small block performance is not too bad either, compared to others in the database.

CrystalDiskMark with Kogan RTS5301


It performs a little faster on the read with the Realtek based reader, but is slightly slower/the same on writes. It’s good to see the card maintains good performance across the two tested readers.

H2testw with Transcend RDF8


Is this a surprise? Hardly. Sandisk is a byword for quality – and that can only be the case if their products live up to their specifications. In the H2testw benchmark, no failures of the flash were found, with the write averaging at 14.9Mb/s, and read averaging at 41.2Mb/s. This isn’t quite the 48Mb/s on the packet, but it’s still quite a bit above the 30Mb/s on their “older” packet designs. It’s probably just a marketing choice so as not to be unfairly compared to other manufacturers who may also put slightly inflated “up to” figures on their packages.


Go to a decent retail establishment, pay the right price, get the right stuff. What a shame it isn’t this simple when it comes to eBay sellers. At least, here, I have documented what a genuine Sandisk 128Gb Ultra UHS-I MicroSDXC card looks like, along with the packaging and validated its performance. While it doesn’t quite meet the new 48Mb/s “up to” label, it blasts past the 30Mb/s claims of the older range of packages and performs consistently with the rest of the Ultra series of cards. It easily surpasses Class 10 requirements for sequential writes, and is the highest capacity card available to date. This makes it easy to recommend, provided you are buying a genuine product.

The performance test, CID and CSD databases will be updated shortly with the results of this review.

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