SanDisk ULTRA 64GB microSDXC Card Class 10 review, lots of storage on the cheap


High capacity microSD cards offering 64 GB storage have been introduced almost a year ago at a rather high cost (more than $150/€150). Since then, prices have considerably dropped and these little cards are now quite affordable (under €50, £40 or $65) and offer a great accessory to increase your tablet storage space.
The SanDisk ULTRA 64GB card we are checking in this article offers a great Class 10 speed and follows the SDXC format (Secure Digital eXtended Capacity) that breaks the limit of 32 GB from the SDHC card standard.


SanDisk ULTRA 64GB microSDXC packaging and specifications (SDSDQU-064G-U46A product #)

SanDisk gives the following specifications for their product:
  • Class 10 Class 10 UHS-I speed (10 Mbytes/s writing speed)
  • durable Design: Waterproof, X-ray proof, temperature proof (-13 to 185 degrees Fahrenheit), and shockproof
  • includes an SD card adapter for compatibility with SD-enabled devices, such as cameras, camcorders, and laptops
  • the Ultra microSDHC/microSDXC UHS-I cards are backed by a lifetime limited warranty (see SanDisk site for details)
  • SANDISK_Micro_SXHC_64GB_front_DSC_0298_cSANDISK_Micro_SXHC_64GB_back_DSC_0316_c

    Sandisk Ultra 64GB MicroSDXC

    AMAZON USAUsually ships in 24 hours$ 46.4
    AMAZON UKUsually dispatched within 24 hours£ 34.99
    AMAZON FRHabituellement expédié sous 24 h43.9 EUR

    SanDisk 64GB ULTRA microSDXC Performance

    The card is rated as Class 10, that asserts a minimum speed of 10 MB per second on non-fragmented sequential writes. UHS-I symbol relates to the Ultra-High Speed (UHS) that provides enhanced clock frequency compared to the original standards.

    We used the following test setup to evaluate the SanDisk 64GB ULTRA microSDXC performance: x86-64 PC, 8 GB RAM, Windows 7, Transcend Multi-Card Reader M3 connected to computer thru USB 2.0 cable.

    CrystalDiskMark 3.0.2 x64 benchmark
    3 test runs, 100 MB test size
    (MB/s = 1,000,000 bytes/s)

    ATTO Disk Benchmark (DISK32) version 2.47 benchmark
    0.5 to 8192 KB transfer size, Forced Write Access, I/O comparison 512 MB total length, random test pattern

    On our test setup with these two benchmarks, we can see the SanDisk 64 GB is a little below the Class 10 specification, with sequential writing speed around 9.5 MB/s, the sequential reading speed is more than the double, with 19.5 MB/s. As usual, these numbers drop when benchmarking random access on the card.

    Based on the sequential access numbers, that mean it would take about 7 minutes to copy a 4 GB file, or one 1 hour and 40 minutes to fill an empty microSDXC card. It’s not super fast, but it’s usually faster than most flash storage equipping tablets and is currently enough for recording or reading compressed 1080p videos streams.

    SanDisk 64GB ULTRA microSDXC compatibility with Android and other devices

    The SanDisk card come pre-formatted with exFAT file system, which can be a problem with some devices, as we will discover below.

    exFAT (Extended File Allocation Table) is Microsoft file system optimized for flash drives, it is supported on Microsoft Windows operating system (Windows XP with updates, Windows Vista SP1, Windows 7, Windows 8), Apple Mac OS X Snow Leopard starting from 10.6.5, Mac OS X Lion and OS X Mountain Lion, Linux support currently requires special drivers installation. Compared to FAT32 where files are limited to 4 GB, one of the biggest feature of the exFAT format is the file size limit of 16 Exbibytes (EiB) which represents (2^60 bytes, that is more than a billion of gigabytes !)

    Wikipedia mentions the following about SDXC compatibility with SDHC

    SDXC host devices accept all previous families of SD memory cards. Conversely, SDHC host devices accept SDXC cards that follow Version 3.0, since the interface is identical, but the following issues may affect usability:
    SDXC cards are pre-formatted with Microsoft’s proprietary and patented exFAT file system, which the host device might not support. Since Microsoft does not publish the specifications of exFAT and its use requires a non-free license, many alternative or older operating systems do not support exFAT for technical or legal reasons. The use of exFAT on some SDXC cards may render SDXC unsuitable as a universal exchange medium, as an SDXC card that uses exFAT would not be usable in all host devices. Since the FAT32 file system supports volumes up to the SDXC’s maximum theoretical capacity of 2 TB as well, a user could reformat an SDXC card to use FAT32 for greater portability between computers (see below). FAT32-formatted SDXC cards can be used in a host device built for SDHC if the host device can handle 64 GB and larger volumes.
    SDHC host devices do not test the new capability bits defined for SDXC 4.0 cards and thus cannot use the new features of SDXC, such as transfer speeds above UHS104 (104 MB/s).

    As you can see on our video, the card is confirmed to come formatted in exFAT format and worked immediately on the PC running Windows 7, we’ll see it is a little more complicated on some Android devices.

    On their website, ARCHOS mentions a “microSD Slot (SDHC compatible up to 64GB)” for their most recent devices such as the GamePad, Gen 10 XS or Titanium, there is even a “(compatible up to 128GB)” for the 101 XS. Actually there is no mention of specific SDXC support and we could hope to see the card immediately supported. We tried the card out of the box on the GamePad and 101 XS, and it resulted in a failure as you can see below, the SDcard is shown as damaged and can’t be formatted by the Android system.



    We had to format the card in FAT32 on a PC to be able to use it on the tablets. We will give full details of the procedure and some extra benchmarks in another article.

    SanDisk ULTRA 64GB microSDXC Card Class 10 on the ARCHOS 101 XS

    SanDisk ULTRA 64GB microSDXC Card Class 10 on the ARCHOS GamePad

    Sandisk Ultra 64GB MicroSDXC

    AMAZON USAUsually ships in 24 hours$ 46.4
    AMAZON UKUsually dispatched within 24 hours£ 34.99
    AMAZON FRHabituellement expédié sous 24 h43.9 EUR


    This site uses Akismet to reduce spam. Learn how your comment data is processed.