Our demand for storage is pretty much insatiable, but companies continue to roll out new products which are larger, faster and sometimes even cheaper than before. Of note is the proliferation of microSD-slots in Android and Windows phones, tablets as well as the use of microSD cards in action cameras which are beginning to demand even higher speeds to support capturing of high quality 4K video.
This post will look at the Toshiba Exceria 64Gb UHS-I Class 3 microSDXC card, model number SD-C064GR7VW060A) which has been sent to me for testing by a friend. This card was (apparently) a chance discovery at a local retail outlet, selling at a reasonable (~$1/gb) price which seems to be great news as Toshiba cards have rarely been seen at retail here.
The package it comes in is mostly blue in colour, and a departure from previous Exceria cards with their “type-x” nomenclature. The box is a thin card box with colour print and silver foil, boasting an impressive 95Mb/s read, 60Mb/s write speed and 64Gb capacity. As with most flash cards, it is “water proof” (compatible? eh?), but this one is Made in Japan. Plastic seals adorn every joint, and an anti-counterfeit hologram is visible on the top tab. As with most Exceria cards, there are warnings not to use the card in adapters – this is because the high speed signalling can be incompatible/cause errors with adapters.
This card differs from the majority of cards on the market, as most of them are still rated in the older Class system, which tops out at class 10 (10Mb/s) denoted by a 10 enclosed in a C. The new UHS class ratings have a number inside a U, and represent the minimum write speed in units of 10Mb/s. This is the first card that I have that is rated for a class greater than UHS Speed Class 1 (i.e. a U with a 1 in it).
This can lead to confusion, as UHS-I cards with Class 10 rating are commonly seen, people may naturally assume that the I in UHS-I represents the speed, but instead it represents the bus speed. There is also a faster UHS-II bus available for even higher performance cards.
So, in short, this is a card that communicates over the UHS-I bus, with a minimum write speed of UHS Speed Class 3 (30MB/s). It can only achieve its maximum speed over the UHS-I bus, with backwards compatibility to various slower “regular” SD card bus speeds but with performance limitations.
The box itself contains text on the back including a disclaimer about usable storage capacity in binary gigabytes. The inside of the box elaborates more about the speed limitations of different SD card bus speeds, and can be accessed by cutting along the dotted line. As this was “on loan”, I didn’t cut it open.
As with most of the “higher end” Exceria cards, this one came in a clear plastic shell which is held by a larger milky-white plastic tray. It’s a bit of overkill if you ask me.
The card itself has standard white printing including the speed information and capacity on the front. A laser etched serial number is also placed on the front. The rear is unmarked, although features a ribbed appearance.
For reference, the card information is as follows:
Capacity: 62,813,896,704 bytes CID: 02544d554330453320f1ea4c3d00e7b1 CSD: 400e00325b590001d3ff7f800a4000e3
The card passed a full fill and multiple passes of verify with no problems at all. The behaviour of the card does deserve some mention, however.
Sequential Read with HDTune Pro and Transcend RDF8
With a new card straight out of the box, the sequential read speed seems to fall somewhat short of the stated 95Mb/s.
However, in a pattern which seems to be consistent with high performance cards, after filling every sector, the card actually gets faster. But only by a little.
The speed averages 78.9Mb/s, with a few variations along the way which are probably due to the flash memory in the card itself, or timing issues between the card and reader. This is still blisteringly fast, in general, and leaves even the Sandisk Extreme (~45Mb/s) in the dust.
Sequential Read with HDTune Pro and Realtek RTS5301
The Realtek based reader didn’t have any compatibility problems using the microSD slot, and was able to negotiate UHS-I with the card straight away. The read performance, however, was less at 67.9Mb/s.
CrystalDiskMark with Transcend RDF8
With the reference CrystalDiskMark benchmark, we see the card scores a much more interesting read score of 82.64Mb/s, which is among the fastest results we see with this reader/USB3.0 controller combination. The write speed also can be seen to hit above 60Mb/s, thus beating the specification on the package. The card appears to perform excellently at sequential large-file streaming-style operation but takes severe penalties at small block 4k accesses. This is not an ideal situation if you wish to use the card with embedded systems, but photographers and videographers should be pretty happy with it.
CrystalDiskMark with Realtek RTS5301
The speeds registered with the Realtek based unit are inferior to that of the Transcend RDF8. This is probably due to performance limitations with the chipset, but it’s good to see it put through a strong result nonetheless.
H2testW with Transcend RDF8
A nearly full write and verify of the filesystem was completed without error. The speeds with the RDF8 were slightly below the CrystalDiskMark results, likely due to the additional overhead of checking the test data.
The card seems to be one of the few cards on the market which has a UHS Speed Class rating faster than 1, and it seems to perform relatively well.
The card provides read and write performance very similar to the full size Exceria Type2, but in a microSDXC form factor. The high speeds generally applied only to large sequential accesses, with significant penalties for small 4k block accesses, making this card a good choice for photographers and videographers, but a poor choice for embedded systems users. The price is very competitive, especially when compared with the main market competitors, and it is Made in Japan, which should mean quality.
That being said, it doesn’t mean that other cards on the market which are only UHS Speed Class 1 are slower. They may not have been qualified for speed class 3, but may still be able to offer 30Mb/s or faster writes (as the database seems to show). Of course, devices that mandate a certain UHS Speed Class will still require those certified cards. Maybe this is a sign we will see more UHS Speed Class 3 marked products on the shelves soon.