Lexar this past week introduced its new family of A2-class microSD cards, the Lexar High-Performance 633x A2. Supporting the highest Application Performance class, the new microSD card is designed in particular for smartphones that need additional storage space for applications. Overall the Lexar High-Performance 633x family of microSD cards is fairly diverse; the cards range in capacity from 16 GB to 512 GB in capacity, and not all of the cards meet an App Performance class standard. Indeed, only the new 512 GB card meets the A2 class standard, while the medium-sized cards are A1 class.

Under the hood, all the cards use the UHS-I bus and are rated for 95 MB/s – 100 MB/s reads as well as 45 MB/s – 70 MB/s writes. Most of the cards in the lineup support the Video Speed Class 30 spec, therefore offering at least 30 MB/s sequential write speeds. As for operating temperature range, it is pretty standard: from 0° to 70° C (32°F to 158°F), which is good enough for everyone except those using specialized devices to work in extreme conditions.

The key feature of the Lexar High-Performance 633x range is of course support for A1 and A2 App Performance specifications, for use with Android phones that need more space for applications. While A1 cards are pretty common these days, A2 cards are still rare partly because they require a more sophisticated (and expensive) controller and partly because not all of their features can be experienced on commonly available hosts.

As we've mentioned before, A2-badged microSD cards mandate a random performance of at least 4000 read IOPS and 2000 write IOPS (vs. 1500/500 read/write IOPS mandated by the A1). Meanwhile, A2-compliant controllers have to support such functions as command queuing (with a minimum depth queue of 2 and a maximum depth queue of 32) to optimize random read performance, caching to hit write performance targets, as well as self-maintenance capabilities. Though to get the most out of an A2 card, the host also needs to support command queuing to guarantee the device's read performance.

Lexar High-Performance 633x microSD Cards
  512 GB 256 GB 128 GB 64 GB 32 GB 16 GB
Sequential Read Speed 100 MB/s 95 MB/s
Sequential Write Speed 70 MB/s 45 MB/s ?
Minimum Sequential Write Speed 30 MB/s 10 MB/s
Minimal Random Read Speed 4000 IOPS 1500 IOPS ?
Minimal Random Write Speed 2000 IOPS 500 IOPS ?
Operating Temperatures 0° to 70° C (32°F to 158°F)
Interface UHS-I
Availability Q4 2018
SDA Labels A2, V30, U3 A1, V30, U3 A1, V10, U1 U1
Part Numbers LSDMI512BBNL633A

Lexar’s High-Performance 633x family of microSD are already available from retailers like Amazon. The models featuring capacities up to 256 GB are priced up to $179.99. The top-of-the-range 512 GB A2-compliant model is expected to hit the market shortly at a price of $299.99.

Related Reading:

Source: Lexar

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  • Xajel - Tuesday, November 6, 2018 - link

    So how much data my fuel tank can hold ? 70L = app 18.5gal.
  • PeachNCream - Tuesday, November 6, 2018 - link

    "Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway."
    -Computer Networks, 3rd ed., p. 83

    Replace tapes with microSD cards?
  • harrkev - Monday, November 5, 2018 - link

    Just a note, but this is NOT the Lexar that everybody remembers. Micron purchased Lexar and eventually sold the name. This brand is now owned by Longsys, a Shenzen, China-based flash memory company.
  • nimi - Tuesday, November 6, 2018 - link

    I honestly did not know that, thanks for the heads up. Steering clear of Lexar from now on.
  • frodesky - Monday, November 5, 2018 - link

    So which phones actually support A2 cards these days?
  • haukionkannel - Tuesday, November 6, 2018 - link

    Pixel phones would if They would have se card slot ;)
    Actually good question and I think that there just Are not so Many phones that support that.
    Even Samsun Galaxy s9 has A1 sd slot, not a2. Maybe next year?
  • haukionkannel - Tuesday, November 6, 2018 - link

    There seems not not to be any phone at this moment...


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