Digital cameras and camcorders employ memory cards (flash-based removable media) for storage of captured content. There are different varieties of memory cards catering to various performance levels. CompactFlash (CF) became popular in the late 90s, but, has now been overtaken by Secure Digital (SD) cards. Many computing systems (PCs as well as smartphones) also support SD cards for augmenting local storage capabilities. High-end recording systems with fast storage requirements use CFast and/or XQD cards. We recently started in-depth evaluation of the performance of various memory cards. SanDisk sent us a SDXC, two microSDXC, a CFast 2.0, and a CompactFlash card from their portfolio for review.


SanDisk / Western Digital is one of the very few flash product vendors who manufacture their own flash memory. They have a comprehensive flash product portfolio targeting the content creators market. Their portable external SSDs and high-performance thumb drives take care of the post-ingestion portable storage requirements, while their range of memory cards service the actual in-camera storage market. Lexar (which used to be a division of Micron) has memory cards for all formats currently in use - SD, microSD, CompactFlash (CF), CFast, and XQD. SanDisk targets all formats other than XQD.

SanDisk sent 5 different cards for our evaluation:

  • SanDisk Extreme microSDXC UHS-I 128GB
  • SanDisk Extreme PRO microSDXC UHS-II 128GB
  • SanDisk Extreme PRO SDXC UHS-II 128GB
  • SanDisk Extreme PRO CompactFlash 128GB
  • SanDisk Extreme PRO CFast 2.0 64GB

Each of these five cards were subject to our comprehensive memory card evaluation routine. Readers will get an idea of the out-of-box performance as well as how the performance degrades after extensive usage.

The next four sections will detail the obtained performance numbers. Prior to that, we take a look at the testbed setup and evaluation methodology.

Testbed Setup and Testing Methodology

Evaluation of memory cards is done on Windows with the testbed outlined in the table below. The USB 3.1 Type-C port enabled by the Intel Alpine Ridge controller (It connects to the Z170 PCH via a PCIe 3.0 x4 link) is used for benchmarking purposes on the testbed side. SD and microSD cards utilize the Lexar Professional Workflow SR2 SDHC / SDXC UHS-II USB 3.0 Reader. A microSD to SDXC UHS-II adapter is used for the latter. CF cards utilize the Lexar Professional Workflow CFR1 CompactFlash UDMA 7 USB 3.0 Reader. The readers were placed in the Lexar Professional Workflow HR2 hub and uplinked through its USB 3.0 port with the help of a USB 3.0 Type-A female to Type-C male cable. CFast cards utilize the Lexar Professional Workflow CR2 CFast 2.0 Thunderbolt/USB 3.0 Reader via its Thunderbolt 2 port. The testbed connection was made through the Thunderbolt 3 to Thunderbolt adapter.

AnandTech DAS Testbed Configuration
Motherboard GIGABYTE Z170X-UD5 TH ATX
CPU Intel Core i5-6600K
Memory G.Skill Ripjaws 4 F4-2133C15-8GRR
32 GB ( 4x 8GB)
DDR4-2133 @ 15-15-15-35
OS Drive Samsung SM951 MZVPV256 NVMe 256 GB
SATA Devices Corsair Neutron XT SSD 480 GB
Intel SSD 730 Series 480 GB
Add-on Card None
Chassis Cooler Master HAF XB EVO
PSU Cooler Master V750 750 W
OS Windows 10 Pro x64
Thanks to Cooler Master, GIGABYTE, G.Skill and Intel for the build components

The full details of the reasoning behind choosing the above build components can be found here.

SanDisk Extreme PRO SDXC Performance
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  • imaheadcase - Thursday, November 9, 2017 - link

    I mentioned both those things..You can read ONE memory card micro, or two if one is used in small case as one. Thats it.

    While it seems like no big deal, it takes quite a long time to transfer over them already. If someone sold a single, multiport micro SD card reader to use they would make millions. lol
  • Liltorp - Thursday, November 9, 2017 - link

    Might not be the card that limits you. Often it is the camera and it's interface to the card. Unless you KNOW that some cards can bring this performance.
  • Railgun - Sunday, November 12, 2017 - link

    The issues with these tests and using them as a baseline for camera usage is that’s it doesn’t take into account the camera HW itself. While generally using the fastest card you can will help, generally the camera will write slower, sometimes considerably than these kinds of tests suggest.
  • ET - Thursday, November 9, 2017 - link

    Thanks for the A1 mention. I didn't see that mentioned in the article, and it indeed explains the results. It doesn't matter how it's achieved (cache of otherwise), but it defines a minimum number of IOPS, and that should do the trick.
  • MamiyaOtaru - Wednesday, November 8, 2017 - link

    glad there are at least some random 4k write numbers (CrystalDiskMark screenshots) for those cases where they are used as primary storage, in a Raspberry Pi for instance. Can't expect too much from an SDXC card of course, but some of them are so much worse than others
  • Sarah Terra - Wednesday, November 8, 2017 - link

    3+ year old tech unfortunately

    The extreme pro series has not been updated in quite some time.
  • Gee Ham - Wednesday, November 8, 2017 - link

    Which is the best SD and SDmicro card, because I still don't understand the technical information.
  • Lolimaster - Thursday, November 9, 2017 - link

    For cameras and video cameras I think SD card should be replace by something like compact m.2 SSD's, even sata 250MB/s should be overkill with tons of 4K random writes improvements.
  • SanX - Sunday, November 12, 2017 - link

    Ok, do the test
    1) how many rewrites it will survive. 30, 20? Or just 10?
    2) Do another test: pull the card without Eject. After how many such typical usage events it is dead?

    This kind of overpriced junk does not last.
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    ACMarket is the latest app store for Android users, but with a twist. In ACMarket, you can download cracked apps and games absolutely for free. ACMarket is a free app that is dedicated to provide free cracked apps and games only for Android devices. ACMarket APK is compatible with Android and Windows operating systems. As a new player in the category, ACMarket competes with apps like TweakBox, Amazon Underground etc. that provide the same services.

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