Best microSD card for Surface Pro 4



(Added more HIGH PERFORMANCE cards and results using CrystalDiskMarks. – Aug 9, 2016)

(Published a new article with newer microsd cards – please read this article! – Sep 1, 2017)

It is more than likely that at some point down the road, you will run out of storage space. Whether that’s because you installed too many apps or you have too much files stored, most people will hit into this barrier eventually.

The Surface Pro 4 has multiple ways to expand its storage capacity. One way is to get a USB based external hard drive but that adds bulk which in some ways, defeats the purpose of getting such a light and portable device in the first place.

The solution here is to get a microSD card. But which one? There are so many out there. Which one works the best on your device?

I’ve been ordering 128GB microSD cards from various manufacturers so that I can do some performance comparison tests. Although the title says the article is to determine the best microSD card for Surface Pro 4, I’m sure this applies to older devices and the new Surface Book as well. But for the purpose of this review, I will be using my Surface Pro 4.

Following cards have been tested (so far):

  • Samsung EVO microSDXC 128GB (UHS-1) – added on May 31, 2016
  • Patriot LX microSDXC 128GB (UHS-1) – added on May 31, 2016
  • Silicon Power microSDXC 128GB (UHS-1) – added on May 31, 2016
  • Samsung EVO+ microSDXC 128GB (UHS-1) – added on July 8, 2016
  • SanDisk Ultra microSDXC 128GB (UHS-1) – added on July 8, 2016
  • Lexar 633x microSDXC 64GB (UHS-1) – added on August 9, 2016
  • SanDisk Extreme microSDXC 64GB (UHS-3) – added on August 9, 2016

Each card will be freshly formatted before the beginning of each test. This will give every card a fair chance to perform at equal conditions. Although I am starting with 3 cards, I will be receiving more. As I receive them,  I will update this article and re-post.

I will be using more benchmarking tools in the future as well.

UPDATED (July 8, 2016): Two cards have been added. Both are expected to perform better than the existing cards tested so far and they are priced accordingly.

UPDATED (August 9, 2016): Two more cards have been added. Both of these cards are considered to be two of the top performing sdcards currently offered at the market. In case of SanDisk Extreme, it is a UHS class 3 card. It will be interesting to see if it performs better than the rest of the UHS class 1 cards. Also, a new set of results have been collected using CrystalDiskMarks.


  1. You completely miss that in the long term the Samsung Evo card will probably be the most reliable. I purchase 2 SanDisk Ultra 128gb cards for my Surface Pro 4 and Surface 3 (from a top supplier) and within 2 weeks both were causing errors on reading large files. The cards have been replaced for Samsung Evo Plus, with no issues thus far. The Samsung MicroSD cards – Evo/Evo Plus/Pro are generally highly rated and reliabilty is the most important thing for me. The no brand card is likely cheap from a supplier/manufacturer with little quality control!

    • Good point. I’ll research and add those data into the article. But depending on your usage, even the shorter lasting ones may outlast its usefulness…

      • I had purchased a 128 SanDisk Ultra. I mounted the card and was not able to unmount it till I took it to the dealer who after a bit of jiggling and cussing managed to get it out. The dealer said DONT use SanDisk on Surface Pro 4’s as they are slightly thinner than other variety of MicroSD which results in them getting stuck in the drive. I now use Samsung and Crystal……..

  2. I hope they test the Lexar High-Performance microSDXC 633x 128GB UHS-I. It’s definitely one of the best ones out there. Far better than the results he was getting with any of the first 3 cards he tried. It’s also very reliable. Avg 23MB writes / 79MB reads tested with ATTO.

  3. I have to also chip in that when I benchmark I get different numbers using a benchmark tool such as CrystalDiskMark vs copying a large 3-4GB .iso or .mkv file to the card and watching Windows 10’s “More Details” speed graph. Watching Windows 10’s speed graph, you can see that some USB Flash drives have a shorter or longer length of “burst” speed, and then they drop down to a lower “sustained” speed throughout the rest of the file copy. So far I’ve only noticed this behavior with USB Flash drives, rather than with MicroSD XDHC cards. It’s as if the USB Flash drives themselves have the burst buffer built in where the MicroSD cards are straight up unbuffered raw storage. I suggest you confirm this behavior yourself when you do testing, rather than just posting “benchmark” numbers.

    For example, I don’t really see any burst-to-sustained drop copying from my Surface 4 to a SanDisk Extreme Pro microSDXC U3 64GB (SDSDQXP-064G-G46A) which shows a nearly steady 80.0 MB/s speed on Windows 10’s graph while copying a large .iso file. A Samsung Pro Plus 128GB MicroSDXC U3 (MB-MD128DA/AM) shows about 74.5MB/s doing the same file copy.

    • I recognize that there’s not a single benchmark that can accurately represent user usage patterns accurately, so I intend to expand this article with more benchmarks. That’s another reason why I threw in my own file copying test as well. I’m open to suggestions on the benchmark tools. I still have all the cards, so I can run them on various benchmark tools.

  4. I realize that your article is about the “Best microSD card for Surface Pro 4” but I wanted to chime in that I just recently purchased a SanDisk Ultra 200GB MicroSD, and a BASEQI Aluminum MicroSD Adapter for Microsoft Surface Book. Both appear to be working brilliantly.

    I have a lot of 2D and 3D project assets which could easily fill my Surface Book’s 256GB drive. But now they don’t because of the SanDisk Ultra 200GB MicroSD neatly tucked away in the BASEQI Aluminum MicroSD Adapter. I have about 80GBs left on the MicroSD.

    Of course this only works because I purposely store items on the MicroSD that I’ll never utilize in the Surface Book’s clipboard mode. Which means all my books, and comics still are stored on the primary drive. Though I check them in and out of OneDrive as I read or reference them.

    Anyhow, just wanted to share my MicroSD experience; thus far.

      • The Surface Book has a full-sized SD slot, but that slot is shallow.

        I wanted to expand my Surface Book storage permanently(ish) and leaving a full-sized SD card sticking half out of the side of the device was not an option. So I looked for options; at first I considered low profile SD cards but then discovered the BASEQI Aluminum MicroSD Adapter which was made specifically for the Surface Book thus I could have my permanent(ish) expanded storage and sleek aesthetics too.

        A win-win.

        • I went with the Transcend JetDrive Lite 130 256GB for my Surface Book. It’s shallow so it literally barely sticks out… faster option too. Unfortunately I just killed my surface book with a cup of coffee or I’d have tested it but it specs at 95MB/s Max Read and 60MB/s Max Write (just bought a Surface Pro 4 to replace it, which is why I’m on this particular thread).

    • @David CB
      What type of (write speed) performance do you get with the SanDisk Ultra 200GB on your surface Book. I recently got it for my SP4 and see a write speed of approximately 14MB/s. My plan is to use this as the save location for Adobe light-room catalog and dng imports while I edit my images.
      Any suggestions on a better approach would be appreciated.

  5. Hello

    Thanks for posting these up, I picked up the Sandisk Ultra 128gb card so glad to see my purchase has been validated! I have installed a few games on to it and the only issue I have had so far is Skyrim load times being 2-3 minutes, however I do have a lot of mods installed.

    Would it be a safe assumption to say that the SanDisk Extreme Pro model will outperform the Ultra model?

    • Most likely yes. We will order the Pro card as well for additional tests but I would be very surprised if it isn’t any faster…

  6. John, many many thx! Very valuable results. I’m purchasing the SanDisk Ultra 128GB microSDXC (UHS-1) based on your benchmarks. I may get a Class 3 latter when they get cheaper and, hopefully, you’ll have benchmarked them as well (y)

  7. Maybe it’s just a fluke, but I picked up 2 ADATA 256GB Micro SD cards for my SP3 and mount them as an extension of my C:\ drive and they perform flawlessly. I have no issues with transfer speeds while using Adobe After Effects CS6. Can’t go wrong with a pair of cards for $18. Of course an external backup is always done just in case of a catastrophic failure, but so far so good after 6 months of constant use.

    • very useful article. tks, John. if I can slide off-topic, what is the conventional medium to do an external backup to. ? Currently, I use 1TB HD (USB3) . Is that the easiest way to go.? Or is there a faster adaptor/cable? Suggestions? Thanks.

  8. Hello, I would like to make a request … and ‘can test the card Sandisk 128 MB Micro SD Extreme Pro?
    It ‘a sdxc uhs3, read speeds up to 275MB / s, write speed up to 100MB / s. Standard UHS-II speeds class U3 … It ‘compatible with the Surface Pro 4?
    Thank you.

  9. Hello!
    Have you tried the new Samsung Pro Plus 128GB MicroSDXC Class10 Memory Card? I guess is one of the best ones out there.
    I am running of space in my SP4 and I am getting confused on which one to get. I see that you have tested the Samsung EVO microSDXC 128GB & Samsung EVO+ microSDXC 128GB (UHS-1) , Is it possible to install apps like Matlab or Photoshop on this cards other than documents and pictures?

  10. It looks to me that the test run on the Sandisk Extreme microSDXC 64 GB is wrong. The test result is very similar to the test run on C-drive on my pro 4. Are you sure you remembered to select the right drive?

  11. I have both the SanDisk Ultra 128 GB and Lexar Pro 128 GB (U3) cards tested in my SP4. With both I see 80-90 MB/s sequential reads in CrystalDiskMark BUT if I put the Lexar card in the USB 3.0 adapter that comes with it I see 180-200 MB/s sequential reads and almost 100 MB/s writes. This certainly seems to suggest a limit on the SD Card slot. Either that or there’s a big cache in that adapter.

      • Not yet but after I did some more searching it sounds like people have identified the SD Card controller chip in the SP4 (Realtek RTS5304) and it only supports UHS-I. I think the U3 card is still worth using though since it does have a large advantage in sequential writes and random reads which is important if you’re using it for ‘permanent’ storage rather than just transferring files from one device to another. The seq writes are not much slower than a spinning 7200rpm disk at least.

  12. All of this research and comments are very helpful. I am running out of space and need to buy something this weekend. I thought buying 512 GB in the Surface Pro 4 would be enough but between work and personal it did not last long. I want to move iTunes and personal pictures + documents to the SD card. Which card would you suggest? I am looking for at least 256 GB but would like to go up to 512 GB if possible. Thoughts?

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