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Published January 13, 2018

Whichever model of Gemini PDA you choose, it already comes with a very healthy 64GB of on-board storage.  Once you take into account the installed Android and Linux operating systems however, and then the space occupied by all your apps, and system and temporary files, that space will very quickly be significantly reduced.  Many Gemini owners therefore will want to expand their storage with the addition of a MicroSD card.

The Gemini supports MicroSD cards up to 256GB (a quarter of a terabyte) in size, and that’s what I’ll be reviewing here.  256GB MicroSD cards still aren’t commonplace, largely because they’re still expensive.  The 256GB Evo Plus card retails on Samsung’s US website for a whopping $250, which is a considerable investment when compared to the cost of the Gemini PDA itself, though it can be found more cheaply if you shop around with Amazon selling it at the time of writing for $130, a considerable saving.  It’s still very expensive though, so is it a good investment?

The Samsung Evo Plus range are microSDXC cards with support for read speeds up to 100MB/s and write speeds of 90MB/s and currently sit at the very top of Samsung’s range, coming in sizes from 16GB upwards.  The package includes a full SD size adapter, which can be useful if you are transferring files to the Gemini from a PC or Mac, and Samsung proudly boast the cards can handle full 4K video, played in real-time.

I didn’t have the software to properly test the throughput of the Samsung 256GB Evo Plus MicroSD card, but a very thorough series of tests was performed by website, The SSD Review, and they concluded…

For many, the three main selling points are price, capacity, and performance. By packing the teeny tiny Samsung EVO Plus with their latest 48-layer V-NAND, Samsung is able to deliver a well-balanced, record breaking product. Due to its bleeding edge technology, great performance, and large capacity, it has earned our Editor’s Choice award! If you need high capacity in a small form factor, this is the microSD card for you.

While there are a great many MicroSD cards on the market, if you’re after the largest capacity your Gemini can support, and are happy with the very hefty price tag, the Samsung 256GB Evo Plus is a clear winner.  If however you’re happy to wait, SD card prices regularly fall as higher capacities are introduced, and production and supply increases.  In six to nine months time, this should make the card significantly cheaper.


  1. Jon Crawford Jon Crawford

    “the Samsung 256GB Evo Plus is a clear winner” … against what?

    Personally I would go for the Sandisk Ultra 200GB – current (13/01) UK prices make it half the price of the Sandisk 256GB but obviously only “56GB” less.

    • I agree, the 200GB cards currently available are significantly cheaper and better value, but that’s why I said “…if you’re after the largest capacity your Gemini can support” 🙂 I’m certain we’ll review other MicroSD cards in the future, and perhaps even have an overall value-for-money feature. For now though, this is a single review of a single card, which can only be compared to cards of the same capacity.

      • Jon Crawford Jon Crawford

        Crikey peeps, I’ve been out=Miked 🙂 Although I might try a 400GB card in my Gemini when I finally get the thing; if a 256GB works then a 400GB will work too. Most OEM’s will quote 256GB as a max as that’s basically the maximum available at the time of testing the reader hardware. I’ve got a HTC U11 running with a 400GB, and HTC only quote 256GB max.

        • Be careful with that if you’re buying one especially, as Planet say that 256GB is the ceiling. However if you try the 400GB card and it *does* work, PLEASE feed back to us here and on the Facebook group, as I’d certainly want to buy one 🙂

          • Jon Crawford Jon Crawford

            Mike, 256GB and 400GB cards use the same technology, they just have different page sizes; 256GB being 8 layers x 32GB page, and 400GB being 8 layers x 50 GB page. As the device can read a 8 layer SD card (aka a 256GB), it shouldn’t have a problem with 400GB unless Planet have put limit on the page size – which would invalidate their SD card accreditation. Also, as Paul M correctly says below, fake SD cards are an issue; the fake SD cards identify themselves as a X layer x Y page size, but physically have a lower layer and/or page count.

          • It’s the same version of the SDXC standard they’re using; theoretically the hardware shuld support cards upto 2TB.

  2. Paul M Paul M

    It’s very important to only buy memory cards
    DIRECTLY from reputable suppliers, e.g. Amazon, newegg, ebuyer etc. Never from eBay, never from Amazon marketplace.
    There are many fakes, often almost impossible to tell apart. Many have reduced capacity, don’t perform well, have lots of errors, or will fail prematurely.

    • This is always good advice. Thanks Paul 🙂

    • Khalid W Khalid W

      Very good point Paul!

      I bought a “Sandisk” on the cheap once.
      It was supposed to be 16gb, but I can only access 10gb. Also it died on me after a few weeks use.

      Lesson learned: There is a price to pay for buying something ridiculously cheap. 🙁

  3. gidds gidds

    Well, there’s often one good way to tell the fake ones: price — or rather lack thereof.  If the going rate for e.g. 256GB USB sticks is £70–100, then you KNOW that a £5–15 one is not going to be legit!  Especially if it’s some dodgy brand you’ve never heard of (or even unbranded)…

    That’s not the only type of dodgy one, though.  For example, some cheap brands seem to lack the usual thermal protection.  I got some USB sticks at ~20% under the going rate; they had the rated capacity and high transfer speed, but I inadvertently killed one by trying to fill it in one go.  Since then, I’ve been careful not to write too much in one go (e.g. 20GB), and prevent them getting too hot, and the rest have all behaved perfectly.

    Of course, reputable brands don’t suffer that problem.  So it’s far safer to choose a Sandisk, Samsung, PNY, Kingston, Integral, or Transcend — directly from a reputable supplier, so you know it’s genuine.

    BTW, I’ve already obtained a Samsung Evo Select card for when my Gemini arrives; am I missing out on much by not having an Evo Plus?

  4. Michael Smith Michael Smith

    I agree with Jon Crawford. I too was curious as to why Gemini would only support up to 256GB and no larger, when the SDXC standard specifies up to 2TB sizes. I would expect the Gemini to support the SanDisk 400GB micro SD cards, and even larger sizes that get introduced in the future such as the recently announced Integral 512GB micro SD card.

  5. Riccardo Dusi Riccardo Dusi

    2 march on Facebook page Mr. Kei Uchiumi have post a screenshot and wroote: “Sandisk 400GB sd card works well after formatting.”

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